JP7358356B2 - High transmittance light control film - Google Patents

Description

FIG. 2 is a cross-sectional view of an embodied light control film. FIG. 1b shows the polar blocking viewing angle of the light control film of FIG. 1a; FIG. 3 is a perspective view of a microstructured film of a comparative example. FIG. 2 is a perspective view of a microstructured film. 1 is a schematic cross-sectional view of an exemplary method of manufacturing a light control film; FIG. FIG. 2 is a perspective view of a light control film further comprising a cover film combined with an adhesive layer. 1 is a schematic perspective view of a backlit display with an embodied light control film; FIG. 2 is a plot of brightness versus viewing angle for various light control films. 1 is a schematic cross-sectional view of an exemplary light control film applied to a window of an enclosure such as a building, residence, or vehicle; FIG. 1 is a schematic plot of transmittance versus wavelength for a light control film. 1 is a schematic diagram of an exemplary application where a light control film is applied to an airplane or aircraft; FIG. 1 is a schematic cross-sectional view of an exemplary optical communication system including a light control film in combination with a retroreflector. FIG. 1 is a schematic cross-sectional view of an exemplary wearable optical communication system including a light control film and a wristwatch having a pulse sensor. FIG.

Although various light control films have been described, the industry would find advantages in light control films suitable for use as privacy films with improved properties such as improved on-axis transmission.

In one embodiment, a light control film comprises a light input surface, a light output surface opposite the light input surface, and alternating transmissive and absorbing regions disposed between the light input surface and the light output surface. is explained.

In one embodiment, the absorbent region has an aspect ratio of at least 30.

In some embodiments, the alternating transmitting and absorbing regions have a relative transmittance (measured with a conoscope) of at least 75% at a viewing angle of 0 degrees.

In another embodiment, the alternating transmission and absorption regions are at least 35, 40, 45 for wavelengths in the range of 320-400 nm (UV), measured at a viewing angle of 0 degrees using a spectrophotometer. , or has a transmittance of 50%.

In another embodiment, the alternating transmission and absorption regions are at least 65, 70, 75 for wavelengths in the range of 700-1400 nm (NIR), measured using a spectrophotometer at a viewing angle of 0 degrees. , or 80%, or a combination thereof.

In yet another embodiment, a light source comprising a light input surface, a light output surface opposite the light input surface, and alternating transmissive and absorbing regions disposed between the light input surface and the light output surface. A control film is described. The absorbing regions block light at the light input and light output surfaces, and the maximum blocked surface area is less than 20% of the total alternating transmitting and absorbing regions.

In another embodiment, the absorbent region includes a plurality of particles having a median particle size of less than 100 nanometers.

In another embodiment, the absorbent region includes a polyelectrolyte.

In some embodiments, the light control film further comprises additional layers such as a top coat or adhesive and a cover film, and the total light control film has defined transmission properties as described herein. .

In another embodiment, the light control film comprises a first light control film that is simply described as being disposed over a second light control film. The second light control film can also have absorbing regions having an aspect ratio of at least 30.

Various optical communication systems with the light control films described herein are also described.

In yet another embodiment, a microstructured film is provided with a plurality of light transmissive regions interleaved with channels, the film comprising:
providing a microstructured film, the microstructured film having a surface defined by a top surface and sidewalls of a light-transmitting region and a bottom surface of a channel; and applying an organic light-absorbing material to the surface;
removing at least a portion of the light-absorbing coating from the top surface of the light-transmitting region and the bottom surface of the channel;
A method of making a light control film is described.

In yet another embodiment, a microstructured film is provided with a plurality of light transmissive regions interleaved with channels, the microstructured film covering the top and sidewalls of the light transmissive regions and the bottom surface of the channels. applying a light-absorbing material to the surface by layer-by-layer self-assembly, and applying a light-absorbing coating from the top surface of the light-transmitting region and the bottom surface of the channel. A method of making a microstructured film is described including removing at least a portion.

In one embodiment, a light control film ("LCF") is described. Referring to FIG. 1a, which is a cross-sectional view of an exemplary LCF 100, the LCF includes a light output surface 120 and an opposite light input surface 110. Light output surface 120 is typically parallel to light input surface 110. LCF 100 includes alternating transmissive regions 130 and absorbing regions 140 disposed between a light output surface 120 and a light input surface 110.

In one embodiment, as shown in FIG. 1a, the transmissive region 130 is typically integral with a land region "L", which is a connection between the land region and the base portion 131 of the transmissive region 130. This means that there is no interface between them. Alternatively, the LCF may lack such a land region L, or an interface may exist between the land region L and the transparent region 130. If an interface is present, land regions are located between the alternating transmissive and absorbing regions 130 and 140 and the light input surface 110.

Alternatively, in another embodiment, surface 120 may be a light input surface and surface 110 may be a light output surface. In this embodiment, the land areas are located between the alternating transmissive and absorbing areas 130 and 140 and the light output surface.

Transparent region 130 may be defined by a width "W _T ". With the exception of land areas "L", transmissive area 130 typically has the same nominal height as absorbing area 140. In typical embodiments, the height H _A of the absorbent region is at least 30, 40, 50, 60, 70, 80, 90, or 100 microns. In some embodiments, the height is less than or equal to 200, 190, 180, 170, 160, or 150 microns. In some embodiments, the height is 140, 130, 120, 110, or 100 microns or less. LCFs typically include multiple transparent regions having nominally the same height and width. In some embodiments, the transmissive region has a height "H _T ", a maximum width "W _T " at its widest portion, and an aspect ratio H _T /W _T of at least 1.75. In some embodiments, H _T /W _T is at least 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, or 5.0. In other embodiments, the aspect ratio of the transmissive region is at least 6, 7, 8, 9, 10. In other embodiments, the aspect ratio of the transmissive region is at least 15, 20, 25, 30, 35, 40, 45, or 50.

Absorbing region 140 has a height “H _A ” defined by the distance between bottom surface 155 and top surface 145, such top and bottom surfaces typically intersecting light output surface 120 and light input surface 110. is parallel to Absorbing regions 140 have a maximum width “W _A ” and are spaced apart along surface light output surface 120 by a pitch “P _A ”. The absorbent region also has a length " _LA ", as shown in the perspective view of FIG. Width is typically the smallest dimension. Height is typically greater than width. Length is typically the largest dimension. In some embodiments, the length can span the entire length of a piece of film or can span the length of an entire roll of film.

The width _WA of the absorbent region at the base (ie, adjacent the bottom surface 155) is typically the same nominally as the width of the absorbent region adjacent the top surface 145. However, if the width of the absorbent region at the base is different from the width adjacent the top surface, then the width is defined by the maximum width. The maximum widths of the multiple absorbing regions can be averaged over an area of interest, such as the area where transmittance (eg, brightness) is measured. LCFs typically include multiple absorption regions having nominally the same height and width. In typical embodiments, the absorbent region typically has a width of 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 micron or less. In some embodiments, the absorbing region typically has a width of no more than 900, 800, 700, 600, or 500 nanometers. In some embodiments, the absorbing region has a width of at least 50, 60, 70, 80, 90, or 100 nanometers.

The absorbing region can be defined by an aspect ratio of the height of the absorbing region divided by the maximum width of the absorbing region (H _A /W _A ). In some embodiments, the aspect ratio of the absorbing region is at least 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In a preferred embodiment, the height and width of the absorbent region are selected such that the absorbent region has a higher aspect ratio. In some embodiments, the aspect ratio of the absorbing region is at least 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or It is 100. In other embodiments, the aspect ratio of the absorbing region is at least 200, 300, 400, or 500. Aspect ratios can range up to 10,000 or more. In some embodiments, the aspect ratio is less than or equal to 9,000, 8,000, 7,000, 6,000, 5,000, 4,000, 3000, 2,000, or 1,000.

As shown in FIG. 1b, LCF 100 includes alternating transmissive regions 130 and absorbing regions 140, and an interface 150 between transmissive regions 130 and absorbing regions 140. Interface 150 forms a wall angle θ with a line 160 perpendicular to light output surface 120 .

The larger the wall angle θ, the smaller the transmittance at normal incidence, in other words at a viewing angle of 0 degrees. Smaller wall angles are preferred so that the transmission of light at normal incidence can be as large as possible. In some embodiments, the wall angle θ is less than 10, 9, 8, 7, 6, or 5 degrees. In some embodiments, the wall angle is less than or equal to 2.5, 2.0 degrees. It is 1.5, 1.0, 0.5, or 0.1 degrees or less. In some embodiments, the wall angle is zero or approaches zero. If the wall angle is zero, the angle between the absorption region and the light output surface 120 is 90 degrees. The transparent area can have a rectangular or trapezoidal cross section, depending on the wall angle.

When incident light undergoes total internal reflection (TIR) at the interface between the absorption region and the transmission region, the transmittance (for example, the brightness of visible light) can be increased. Whether a light beam will undergo TIR can be determined from the angle of incidence with the interface and the difference in refractive index of the materials in the transmitting and absorbing regions.

As shown in FIG. 1b, the transmissive regions 130 between the absorbing regions 140 have an interfacial angle θ _I defined by the geometry of the alternating transmissive regions 130 and the absorbing regions. As shown in FIGS. 1a and 1b, the interfacial angle θ _I can be defined by the intersection of two lines. The first line extends from a first point defined by the bottom and sidewall surfaces of the first absorbent region and a second point defined by the top and sidewall surfaces of the nearest second absorbent region. . The second line extends from a first point defined by the top and sidewall surfaces of the first absorbent region and a second point defined by the bottom and sidewall surfaces of the second absorbent region.

The polar blocking viewing angle θP is equal to the sum of the polar blocking viewing half angle θ1 and the polar blocking viewing half angle θ2, each of which is measured from the normal to the light input surface 110. In an exemplary embodiment, the polar blocking viewing angle θP is symmetrical and the polar blocking viewing half angle θ1 is equal to the polar viewing half angle θ2. Alternatively, the polar blocking viewing angle θP may be asymmetric, such that the polar blocking viewing half angle θ1 is not equal to the polar blocking viewing half angle θ2.

Brightness can be measured according to the test method described in the Examples. The brightness can be measured on alternating transmitting and absorbing regions as shown in FIG. 1a or on a total light control film that can further include a cover film as shown in FIG. 4. Relative transmittance (e.g. visible light brightness) is measured using a light control film comprising alternating transmitting and absorbing regions and optionally other layers at a defined viewing angle or range of viewing angles; It is defined as the percentage of brightness between the reading without the light control film (i.e. baseline). Referring to FIG. 6, the viewing angle can range from -90 degrees to +90 degrees. A viewing angle of 0 degrees is orthogonal to the light input surface 110, while viewing angles of -90 degrees and +90 degrees are parallel to the light input surface 110.

For example, referring to FIG. 6, the on-axis baseline luminance is 2100 Cd/ ^m2 . EX6 has an on-axis brightness of 1910 Cd/ ^m2 . The relative transmittance (eg, brightness) is therefore 1910 Cd/m ² /2100 Cd/m ² multiplied by 100, which is equal to 91.0%. Unless otherwise specified, relative transmittance refers to the relative transmittance of visible light having a wavelength range of 400 to 700 nm, as measured by the conoscopic test method described in more detail in the Examples.

The alternating transmitting and absorbing regions, or total LCF, can exhibit large relative transmittance (eg, brightness) at a 0 degree viewing angle. In some embodiments, the relative transmittance (eg, brightness) is at least 75, 80, 85, or 90%. Relative transmission (eg, brightness) is typically less than 100%.

The alternating transmitting and absorbing regions, or the total LCF, can exhibit high transmission of other wavelengths of light at a viewing angle of 0 degrees. The transmittance of near infrared (NIR) light with a wavelength range in the range of 700-1400 nm and ultraviolet (UV) light with a wavelength range of 320-400 nm is explained in more detail in the examples. means the transmittance measured by a spectrophotometric method.

In some embodiments, the alternating transmission and absorption regions, or total LCF, is at least 50, 55, 60, 65, 70 for wavelengths in the range of 700-1400 nm (NIR) at 0 degree viewing angle. , 75, or 80% transmittance. In some embodiments, the alternating transmitting and absorbing regions, or the total LCF, provides at least 50% or 60% transmission for wavelengths in the range of 320-400 nm (UV) at a viewing angle of 0 degrees. have. The transmittance may be for a single wavelength of a wavelength range, or the transmittance may be an average transmittance over the entire wavelength range.

Alternatively, the alternating transmitting and absorbing regions, or the total LCF, can exhibit low transmission of light at other wavelengths at a viewing angle of 0 degrees. The materials of the base film (eg PET) and the light-transmissive regions and land layer may have high transmission of visible and NIR light, but still have lower transmission of UV light. Furthermore, by including a (eg color shifting) film, the transmission of both UV and NIR light can be substantially reduced, while exhibiting high transmission of visible light. In some embodiments, the alternating transmission and absorption regions, or total LCF, is less than 50, 45, 40, or 30% for wavelengths in the range of 700-1400 nm (NIR) at 0 degree viewing angle. It has a transmittance of . In some embodiments, the alternating transmission and absorption regions, or total LCF, is 50, 45, 40, 35, 30, for wavelengths in the range of 320-400 nm (UV) at 0 degree viewing angle. It has a transmittance at a viewing angle of less than 25, 20, 15, 10, or 5%. The transmittance may be for a single wavelength of a wavelength range, or the transmittance may be an average transmittance over the entire wavelength range.

In typical embodiments, the LCF has significantly lower transmission at other viewing angles. For example, in some embodiments, the relative transmittance (e.g., visible light brightness) at viewing angles of -30 degrees, +30 degrees, or average viewing angles of -30 degrees and +30 degrees is 50, 45, 40, 35 , 30, or 25%. In other embodiments, the relative transmittance (e.g., brightness) at viewing angles of 30 degrees, +30 degrees, or average viewing angles of -30 degrees and +30 degrees is less than 25, 20, 15, 10, or 5%. . In some embodiments, +/-35, +/-40, +/-45, +/-50, +/-55, +/-60, +/-65, +/-70, +/- The relative transmittance (eg, brightness) at a viewing angle of 75 or +/-80 degrees is less than 25, 20, 15, 10, or 5%, alternatively less than 5%. In some embodiments, the average relative transmittance (e.g., brightness) for viewing angles spanning +35 to +80 degrees, -35 to -80 degrees, or the average viewing angle of these ranges is 10, 9, 8, 7. , 6, 5, 4, 3, or less than 2%.

Alternating transmitting and absorbing regions, or the total LCF, can exhibit significantly lower transmission of light at NIR or UV wavelengths at other viewing angles. For example, in some embodiments, the alternating transmissive and absorbing regions, or total light control film, may be 50, 45, 40, 35, It has a transmittance of less than 30, 25, 20, 15, 10, or 5%. In some embodiments, the alternating transmissive and absorbing regions, or the total light control film, is 50, 45, 40, 35, 30, 25 in the wavelength range of 320-400 nm (UV) at a viewing angle of 30 degrees. , 20, 15, 10, 5, 4, 3, 2, or less than 1%. In some embodiments, the transmission of light at NIR or UV wavelengths at a viewing angle of 60 degrees is also within the aforementioned range, and is typically less than the transmission at 30 degrees. In some embodiments, the alternating transmissive and absorbing regions, or total light control film, has 5, 4, 3, 2, or It has an average transmittance of less than 1%.

Accordingly, the light control films described herein can exhibit various combinations of high and low transmission properties at various viewing angles for various wavelengths of light (visible, UV and NIR). can.

In one embodiment, the light control film exhibits high NIR transmission at various viewing angles (e.g., 0, 30, and 60 degrees), but still has lower visible and UV transmission, as mentioned above. low. The light control film has a transmittance of at least 60, 65, 70, 75, or 80% for wavelengths in the range of 700 to 1400 nm (NIR) and 700 to 1400 nm (NIR) at viewing angles of 30 and/or 60 degrees. The transmittance can be at least 10, 15, 20, 25, 30, 35, 40, 45, or 50% for wavelengths in the NIR range.

LCFs with significantly lower transmission at "off-axis" viewing angles are suitable for use as privacy films. Although such films allow the viewer to view images directly in front of the display (0 degree viewing angle), the viewer still cannot view such images at an "off-axis" angle. I can't.

Absorbing regions can be characterized in terms of the maximum surface area of the absorbing region that blocks (eg absorbs) light at the light input or output surface. The light input or output side of the light control film can be viewed with an optical microscope (eg, 200X magnification). If the absorption areas are smaller (e.g. W _A is less than 1 micron), a higher resolution microscope (e.g. a scanning electron microscope) can be used to measure the surface area.The maximum width of the absorption areas (i.e. W _A in Fig. 1a) and pitch (i.e. P _A in Fig. 1a) were determined using ImageJ software (such as that available from the National Institute of Health at http://imagej.nih.gov/ij). It can be measured by analyzing optical microscopy images.

FIG. 1c is a perspective view of a comparative example LCF 150 with a light output surface 120 and an opposite light input surface 110. Light output surface 120 is typically parallel to light input surface 110. LCF 700 includes alternating transmissive regions 130 and absorbing regions 140 disposed between light output surface 120 and light input surface 110. For the comparative light control film (CE2), the average maximum width W _A of the (eg 5) absorption regions is 15 microns, as shown in Figure 1c. The average pitch P _A (distance between absorbing areas) is 65 microns. The ratio W _A /P _A is equal to 0.23 or 23%. In other words, the maximum surface area occupied by the absorbing regions is 23% of the total alternating transmitting and absorbing regions of the light output surface 720.

に等しい。例えばＷ_Ｔが３０ミクロンであり、Ｗ_Ａが０．５ミクロンであり、壁角度が３度である場合、

であり、ブロックされた光の総表面積は１７．１％である。 The absorbing regions described herein block (eg, absorb) less light than the comparative light control film. In typical embodiments, the maximum surface area occupied by the absorbing regions is 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, Less than 7, 6, 5, 4, or 3%. The maximum surface area occupied by the absorbing region if the absorbing region has a wall angle of zero, or in other words, the height is perpendicular to the light input and light output surfaces as shown in Fig. 1a. can be calculated in the same way as for the comparative light control film just described (ie, the ratio W _A /P _A ). If the absorbing region has a wall angle greater than zero, the ratio W _A /P _A is equal to all of the light that is blocked as it passes through the film in a direction perpendicular to the light input and light output surfaces. light is not considered. In this embodiment, "d" can be calculated from the wall angle and line 160 perpendicular to the light output surface 120. This total surface area of light blocked is

be equivalent to. For example, if W _T is 30 microns, W _A is 0.5 microns, and the wall angle is 3 degrees, then

, and the total surface area of blocked light is 17.1%.

Absorption regions can be formed by coating the surface of the microstructured film. FIG. 2 depicts an exemplary microstructured film article 200 that can be coated to produce LCFs. The illustrated microstructured film includes a microstructured surface 210 with a plurality of channels 201a-201d on a base layer 260. As shown in FIG. 2, a continuous land layer "L" may exist between the bottom of the channel 205 and the top surface 210 of the base layer 260. Alternatively, channels 201 can extend completely through microstructured film article 200. In this embodiment (not shown), the bottom surface 205 of the trench may coincide with the top surface 210 of the base layer 260. In an exemplary embodiment, base layer 260 is a preformed film that includes a different organic polymeric material than transmissive region 230, as described subsequently.

The height and width of the protrusion (eg, transparent region) 230 is defined by adjacent channels (eg, 201a and 201b). A protrusion (eg, a transparent region) 230 may be defined by a top surface 220, a bottom surface 231, and sidewalls 232, 233 joining the top surface to the bottom surface. The side walls may be parallel to each other. More typically, the sidewalls have the wall angles previously described.

In some embodiments, protrusions (eg, transparent regions) 230 have a pitch "P _T " of at least 10 microns. The pitch is the distance between the start of a first protrusion (eg, a transparent region) and the start of a second protrusion (eg, a transparent region), as shown in FIG. The pitch may be at least 15, 20, 25, 30, 35, 40, 45, or 50 microns. The pitch is usually 1 mm or less. The pitch is typically less than or equal to 900, 800, 700, 600, or 500 microns. In some embodiments, the pitch is typically less than or equal to 550, 500, 450, 400, 350, 300, 250, or 200 microns. In some embodiments, the pitch is 175, 150, 100 microns or less. In typical embodiments, the protrusions are uniformly spaced at a single pitch. Alternatively, the protrusions can be spaced such that the pitch between adjacent protrusions is not the same pitch. In this latter embodiment, at least a portion, typically a majority (at least 50, 60, 70, 80, 90% or more of the total protrusions) have the pitch just described.

The pitch P _A of the absorbing regions is within the same range just described for the light transmitting regions.

The pitch and height of the protrusions (eg, transmissive regions) can be important to facilitate coating of the protrusions (eg, transmissive regions) with a light-absorbing coating. If the protrusions are spaced too closely together, it may be difficult to uniformly coat the sidewalls. If the protrusions are spaced too far apart, the light absorbing coating may not be effective in providing the intended function, such as privacy at off-axis viewing angles.

Absorbing regions are formed by providing a light absorbing coating on the sidewalls of protrusions (eg, transmissive regions) of the microstructured film. The thickness of the light-absorbing coating is equivalent to the width _WA of the absorbing area, as explained above. The absorbing region can be formed by any method that provides a sufficiently thin conformal light absorbing coating on the sidewalls (eg, 232, 233).

In one embodiment, the absorbent region is formed by a combination of additive and subtractive methods.

Referring to FIG. 3, the light control film includes a microstructured film 300 (the microstructured film of FIG. etc.) can be prepared by providing A plurality of protrusions (eg, transparent regions) 330 are separated from each other by channels 301a and 301b. The sidewalls of the protrusion (eg, the transparent region) are coincident with the sidewalls of the channel. The channel further includes a bottom surface 305 that is parallel to or coincident with the top surface of the base layer 360. This method applies light to the (e.g., entire) surface of the microstructured film, i.e., the top surface 320 and side walls 332, 333 of the protrusions (e.g., the transmissive regions), and the bottom surface 305 of the channels separating the protrusions (e.g., the transmissive regions). Further comprising applying an absorbent coating 341. The method further includes removing the coating from the top surface 320 of the protrusion (eg, the transmissive region) and the bottom surface 305 of the channel. In some embodiments, the method further includes filling the channel with an organic polymeric material 345, such as a polymeric resin (e.g., the same) as the protrusion (e.g., the transparent region), and curing the polymeric resin. . If the channels are not filled with cured polymeric resin, they are typically filled with air.

Microstructured articles (eg, microstructured film article 200 shown in FIG. 2) can be prepared by any suitable method. In one embodiment, a microstructured article (e.g., microstructured film article 200 shown in FIG. 2) is produced by (a) providing a polymerizable composition and (b) barely filling the cavities of the master. (c) depositing a bead of polymerizable compound onto a master negative microstructure molding surface (e.g., a tool) in an amount sufficient to (d) curing the composite as described in U.S. Pat. No. 8,096,667. It can be prepared by casting and hardening methods. Deposition temperatures can range from ambient to about 180°F (82°C). The master may be made of a metal such as nickel, chromium-plated or nickel-plated copper or brass, or which is stable under the polymerization conditions and allows clean removal of polymerized material from the master. It may also be a thermoplastic material with surface energy. If the base layer is a preformed film, one or more of the surfaces of the film may optionally be primed to promote adhesion with the organic material in the light transmissive areas, or otherwise may be processed in other ways. In one embodiment, the base layer includes a thermoset acrylic polymer as a primer, such as available under the tradename "Rhoplex 3208" from Dow Chemical of Midland, Michigan.

The polymerizable resin can include a combination of a first polymerizable component and a second polymerizable component selected from (meth)acrylate monomers, (meth)acrylate oligomers, and mixtures thereof. As used herein, a "monomer" or "oligomer" is any substance that can be converted into a polymer. The term "(meth)acrylate" refers to both acrylate and methacrylate compounds. In some cases, the polymerizable compositions include (meth)acrylated urethane oligomers, (meth)acrylated epoxy oligomers, (meth)acrylated polyester oligomers, (meth)acrylated phenol oligomers, (meth)acrylated acrylics Can include oligomers and mixtures thereof.

The polymerizable resin may be a radiation curable polymer resin, such as a UV curable resin. In some instances, polymeric resin compositions useful for the LCFs of the present invention may be modified to the extent that these compositions satisfy the refractive index and absorption properties described herein. 8,012,567 (Gaides et al.).

The chemical composition and thickness of the base layer may depend on the end use of the LCF. In typical embodiments, the base layer can have a thickness of at least about 0.025 millimeters (25 microns), and even from about 0.05 mm (50 microns) to about 0.25 mm (250 microns). good.

Useful base layer materials include, for example, styrene-acrylonitrile, cellulose acetate butyrate, cellulose acetate propionate, cellulose triacetate, polyether sulfone, polymethyl methacrylate, polyurethane, polyester, polycarbonate, polyvinyl chloride, polystyrene, polyethylene naphthalate, Included are polyolefin-based materials such as copolymers or blends based on naphthalene dicarboxylic acid, polyethylene, polypropylene, and polycyclo-olefins, polyimides, and cast or oriented films of glass. Optionally, the base layer can contain a mixture or combination of these materials. In some embodiments, the base layer may be multilayered or may contain dispersed components suspended or dispersed in a continuous phase.

Examples of base layer materials include polyethylene terephthalate (PET) and polycarbonate (PC). Examples of useful PET films include optical grade polyethylene terephthalate available under the trade name "Melinex 618" from DuPont Films of Wilmington, Delaware. Examples of optical grade polycarbonate films include LEXAN™ polycarbonate film 8010, available from GE Polymershape, Seattle, Wash., and Panlite 11, available from Teijin Kasei, Alpharetta, Georgia. 51 are mentioned. In some embodiments, the base layer is a PET film having a thickness of 75 microns. The base layer can have a matte or glossy finish.

Some base layers may be optically active and may act as polarizing materials. Polarization of light through a film can be achieved, for example, by including a dichroic polarizer in the film material that selectively absorbs the light that passes through it. Polarization can also be achieved by including inorganic materials such as aligned mica chips, or discontinuous phases dispersed within a continuous film, such as droplets of light-modulating liquid crystals dispersed within a continuous film. This can be achieved by Alternatively, films can be prepared from microscopic layers of different materials. Polarizing materials within a film can be aligned in a polarizing orientation by using methods such as, for example, stretching the film, applying electric or magnetic fields, and coating techniques.

Examples of polarizing films include U.S. Pat. No. 5,825,543 (Ouderkirk et al.), U.S. Pat. Examples include those described in Patent Nos. 5,612,820 (Shrenk et al.) and 5,486,949 (Shrenk et al.). The use of these polarizer films in combination with prismatic brightness enhancement films is described, for example, in US Pat. No. 6,111,696 (Allen et al.) and US Pat. No. 5,828,488 (Ouderkirk et al.). Commercially available films are multilayer reflective polarizer films such as 3M™ Dual Brightness Enhancement Film "DBEF" available from 3M Company.

In some embodiments, the base layer or cover film is a multilayer film that imparts a (eg, color) wavelength shifting effect as described in US Pat. No. 8,503,122. Suitable color shifting films are described in US Pat. No. 6,531,230 to Weber et al., which is incorporated herein by reference. Other suitable color shifting films include multilayer films produced by spin coating, blade coating, dip coating, evaporation, sputtering, chemical vapor deposition (CVD), and the like. Exemplary films include both organic and inorganic materials. Such films are described, for example, in US Pat. No. 7,140,741, US Pat. No. 7,486,019, and US Pat. No. 7,018,713.

The multilayer optical film may include an ultraviolet reflector, a blue reflector, a visible reflector, or an infrared reflector, as further described in U.S. Pat. No. 9,829,604 (Schmidt) dated November 28, 2017. There may be.

In some embodiments, the multilayer optical film can be characterized as a UV reflective multilayer optical film (i.e., a UV reflector or UV mirror). By UV reflective multilayer optical film is meant a film that has a reflectance at normal incidence of at least 50, 60, 70, 80, or 90% for a bandwidth in the range of 290 nm to 400 nm. In some embodiments, the reflectance at normal incidence for a bandwidth in the range of 290 nm to 400 nm is at least 91, 92, 93, 94, 95, 96, 97, or 98%. The UV reflective multilayer optical film can have low reflectance and high transmittance for visible light. For example, the visible light transmission can be at least 85% or 90%.

In some embodiments, the multilayer optical film can be characterized as a UV blue reflective multilayer optical film (i.e., a UV blue reflector or a UV blue mirror). A UV blue reflective multilayer optical film refers to a film that has a reflectance at normal incidence of at least 50, 60, 70, 80, or 90% for a bandwidth in the range of 350 nm to 490 nm. In some embodiments, the reflectance at normal incidence for a bandwidth ranging from 350 nm to 490 nm is at least 91, 92, 93, 94, 95, 96, or 97%. The UV blue reflective multilayer optical film can have low reflectance and high transmittance for visible light with wavelengths greater than 500 nm. For example, the transmission of visible light with wavelengths greater than 500 nm may be at least 85% or 90%.

In some embodiments, the multilayer optical film can be characterized as a near-infrared reflective multilayer optical film (i.e., near-infrared reflector or near-infrared mirror). Near-infrared reflective multilayer optical film refers to a film that has a reflectance at normal incidence of at least 50, 60, 70, 80, or 90% for a bandwidth in the range of 870 nm to 1100 nm. In some embodiments, the reflectance at normal incidence for a bandwidth ranging from 870 nm to 1100 nm is at least 91, 92, 93, or 94%. In some embodiments, the film exhibits this same near-infrared reflectance at a 45 degree angle. The near-infrared reflective multilayer optical film can have low reflectance and high transmittance for visible light. For example, the visible light transmission can be at least 85%, 86%, 87%, or 88%.

A visible light reflective multilayer optical film (e.g., a visible reflector or a visible mirror) is a film having a reflectance at normal incidence of at least 50, 60, 70, 80, or 90% for a bandwidth in the range of 400 nm to 700 nm. It means. In some embodiments, the reflectance at normal incidence for a bandwidth in the range of 400 nm to 700 nm is at least 91, 92, 93, 94, 95, 96, 97, or 98%. The near-infrared reflectance characteristics of such a broadband reflector are as described above.

In other embodiments, a single multilayer optical film can reflect more than one bandwidth and can be considered a broadband reflector. For example, the multilayer optical film may be a visible reflective multilayer optical film and a near-infrared reflective multilayer optical film. Such multilayer optical films therefore have high reflectance in both the visible and near-infrared bandwidths.

Furthermore, to widen the reflection band, for example two or more multilayer optical film mirrors with different reflection bands are laminated together. For example, a multilayer optical film visible reflector as previously described can be combined with a UV reflector, a UV blue reflector, and/or a near-infrared reflector. Various other combinations can be constructed, as will be recognized by those skilled in the art.

Alternatively, a microstructured article (e.g., microstructured film article 200 shown in FIG. 2) can be prepared by melt extrusion, i.e., a fluid resin onto a master negative microstructured molding surface (e.g., a tool). It can be prepared by casting the composite and curing the composite. In this embodiment, the protrusions (eg, light transmissive regions) are interconnected to the base layer 260 in a continuous layer. The individual protrusions (eg, light transmissive regions) and the connections between them typically include the same thermoplastic material. The thickness of the land layer (ie, excluding the portion resulting from the replicated microstructure) is typically 0.001 to 0.100 inch, preferably 0.003 to 0.010 inch.

The thickness of the land layer may be thinner if the microstructured article (eg, microstructured film article 200 shown in FIG. 2) is prepared from the casting and curing process previously described. For example, the thickness of the land layer is typically at least 0.5, 1, 2, 3, 4, or 5 microns, up to 50 microns. In some embodiments, the land layer has a thickness of 45, 40, 35, 30, 25, 20, 15, or 10 microns or less. In one embodiment, the land layer is 8 microns.

Suitable resin composites for melt extrusion are transparent materials that are dimensionally stable, durable, weather resistant, and easily moldable into the desired configuration. Examples of suitable materials include acrylics with a refractive index of about 1.5, such as Plexiglas brand resin manufactured by Rohm and Haas Company, polycarbonates with a refractive index of about 1.59, thermosetting acrylates, and epoxies. Reactive materials such as acrylates, E. I. Dupont de Nemours and Co. , Inc. Polyethylene-based ionomers, (poly)ethylene-co-acrylic acids, polyesters, polyurethanes, fluoropolymers, silicone polymers, ethylene vinyl acetate (EVA) copolymers, and cellulose acetate butyrate, such as those sold under the brand name SURLYN, by Can be mentioned. Polycarbonates are particularly suitable because of their toughness and relatively higher refractive index.

In yet another embodiment, the master negative microstructured molding surface (eg, tool) can be used as an impression tool as described in US Pat. No. 4,601,861 (Pricone).

Absorbent regions are typically formed by coating the surface of a microstructured film. Various coating methods can be used, including, for example, layer-by-layer (LbL) coating, evaporation, sputtering, reactive sputtering, and atomic layer deposition (ALD).

The light absorbing material useful for forming the light absorbing region may be any suitable material that functions to absorb or block light in at least a portion of the visible spectrum. In typical embodiments, the light absorbing material also absorbs or blocks at least a portion of the UV spectrum and/or the IR spectrum. Preferably, the light-absorbing material can be coated or otherwise provided on the sidewalls of the light-transmitting region, thereby forming a light-absorbing region within the LCF. Exemplary light absorbing materials include black or other light absorbing colorants, such as carbon black or another pigment or dye, or combinations thereof. Other light harvesting materials can include particles or other scattering elements that can function to block light from passing through the light absorbing region. The light absorbing material may be organic, inorganic or a combination thereof. Typically, the light absorbing material is at least partially organic.

If the light-absorbing material (e.g., coating) includes particles, the particles have a median particle size D50 that is less than or equal to the thickness of the light-absorbing material (e.g., coating), in other words, substantially _less than the width of the absorbing region WA. have.

The median particle size is usually less than 1 micron. In some embodiments, the median particle size is less than or equal to 900, 800, 700, 600, or 500 nm. In some embodiments, the median particle size is less than or equal to 450, 400, 350, 300, 250, 200, or 100 nm. In some embodiments, the median particle size is less than or equal to 90, 85, 80, 75, 70, 65, 60, 55, or 50 nm. In some embodiments, the median particle size is 30, 25, 20, or 15 nm or less. The median particle size is typically at least 1, 2, 3, 4, or 5 nanometers. The particle size of the nanoparticles in the absorption region can be measured using, for example, transmission electron microscopy or scanning electron microscopy.

"Primary particle size" means the median diameter of a single (non-agglomerated, non-agglomerated) particle. "Agglomeration" refers to a weak association between primary particles that are held together by charge or polarity and can be broken down into smaller entities. As used herein, "agglomerate" in reference to particles refers to tightly bound particles or strongly fused particles whose resulting external surface area may be significantly less than the sum of the calculated surface areas of the individual components. It means particles that have The forces that hold the aggregates together are strong forces, such as those due to covalent bonds or sintering or complex physical entanglements. Agglomerated nanoparticles can be broken down into smaller entities such as discrete primary particles by surface treatment, but even if surface treatment is applied to agglomerate them, surface-treated aggregates cannot be obtained. It just happens. In some embodiments, most (ie, at least 50%) of the nanoparticles are present as discrete, non-agglomerated nanoparticles. For example, at least 70%, 80%, or 90% of the nanoparticles (of the coating solution) are present as discrete, non-agglomerated nanoparticles.

The concentration of light absorbing nanoparticles is typically at least 10, 15, 20, 25, 30, 35, 40, 45, or 50% by weight of the total light absorbing area. In some embodiments, the concentration of light absorbing nanoparticles is at least 55, 60, 65, 70, or 75% by weight of the total light absorbing area. The concentration of light-absorbing nanoparticles can be determined by methods known in the art, such as thermogravimetric analysis.

In one embodiment, the method includes applying a layer-by-layer light-absorbing coating to the surfaces of the microstructured film, ie, the top and sidewalls of the protrusions and the bottom of the channels.

In some embodiments, the plurality of layers disposed on the surface of the microstructured film comprises at least two layers deposited by a process commonly referred to as a "layer-by-layer self-assembly process." . This process is widely used to electrostatically assemble films or coatings of oppositely charged polyelectrolytes, but also includes other components such as hydrogen bond donors/acceptors, metal ions/ligands, and covalent moieties. The functional groups of can be the driving force for assembling the film. "Polyelectrolyte" means a polymer or compound having multiple ionic groups capable of electrostatic interaction. "Strong polyelectrolytes" retain a permanent charge over a wide range of pH (eg, polymers containing quaternary ammonium or sulfonic acid groups). "Weak polyelectrolytes" possess a pH-dependent level of charge (eg, polymers containing primary, secondary or tertiary amines, or carboxylic acids). Typically, this deposition process involves exposing a substrate with a surface charge to a series of solutions or baths. This can be achieved by immersing the substrate in a liquid bath (also called dip coating), spraying, spin coating, roll coating, inkjet printing, etc. Exposure to a first polyion (e.g., polyelectrolyte bath) solution with a charge opposite to that of the substrate rapidly absorbs charged species in the vicinity of the substrate surface, establishes a concentration gradient, and This will draw more polyelectrolyte from the surface to the surface. Further absorption occurs until a sufficient layer develops to screen the charge of the underlying layer and reverse the net charge on the substrate surface. To allow mass transport and absorption to occur, this exposure time is typically on the order of several minutes. The substrate is then removed from the first polyionic (e.g. bath) solution and subsequently exposed to a series of water wash baths to remove any physically entangled or loosely bound polyelectrolytes. . Following such rinsing (e.g. bath) solution, a second polyion (e.g. polyelectrolyte bath or inorganic oxide nanoparticles) having an opposite charge to that of the first polyion (e.g. bath) solution is then added. bath) The substrate is exposed to the solution. Once again absorption occurs because the surface charge of the substrate is opposite to the charge of the second (eg bath) solution. Continued exposure to the second polyion (eg bath) solution causes a reversal of the surface charge of the substrate. A subsequent rinse can be performed to complete the cycle. This series of steps is said to build up a pair of layers, also referred to herein as a "bilayer" of deposition, and can be repeated as necessary to build up additional layers. pairs can be added to the board.

Some examples of suitable processes include U.S. Patent No. 8,234,998 to Krogman et al., U.S. Patent Application No. 2011/0064936 to Hammond-Cunningham et al., and U.S. Pat. Examples include those listed in the No. Layer-by-layer dip coating can be performed using a StratoSequence VI (nanoStrata Inc., Tallahassee, Fla.) dip coating robot.

In one embodiment, the plurality of bilayers deposited by layer-by-layer self-assembly include an organic polymer polyion (e.g., a cation) and a counterion (e.g., an anion) comprising a light-absorbing material (e.g., a pigment). Polyelectrolyte stack. At least a portion of the cationic layer, anionic layer, or a combination thereof includes a light absorbing material (eg, a pigment) ionically bonded to a polyelectrolyte.

The bilayer thickness and number of bilayers are selected to achieve the desired light absorption. In some embodiments, the thickness of the bilayer, the number of bilayers is determined using a minimum total thickness of the self-assembled layer, and/or a minimum number of layer-by-layer deposition steps. (e.g. absorption) to achieve optical properties. The thickness of individual bilayers typically ranges from about 5 nm to 350 nm. The number of bilayers is typically at least 5, 6, 7, 8, 9, or 10. In some embodiments, the number of bilayers per stack is 150 or 100 or less. The thickness of the stack is equivalent to the width W _A of the absorption area, as already explained.

A light absorbing compound is dispersed within at least a portion of the polyelectrolyte layer. Inorganic compounds such as silica or silicates, and various phosphonocarboxylic acids and their salts, some of which are described in WO 2015/095317, incorporated herein by reference. A variety of polyelectrolytes can be utilized, including.

Polyelectrolyte organic polymers may be preferred because such materials can be more easily removed than inorganic materials by reactive ion etching.

Suitable polycationic organic polymers include linear and branched poly(ethyleneimine) (PEI), poly(allylamine hydrochloride), polyvinylamine, chitosan, polyaniline, polyamidoamine, poly(vinylbenzyltrimethylamine), polydiallyl. Examples include, but are not limited to, dimethylammonium chloride (PDAC), poly(dimethylaminoethyl methacrylate), poly(methacryloylamino)propyl-trimethylammonium chloride, and combinations thereof, including copolymers thereof.

Suitable polyanionic polymers include poly(vinyl sulfate), poly(vinyl sulfonic acid), poly(acrylic acid) (PAA), poly(methacrylic acid), poly(styrene sulfonic acid), dextran sulfate, heparin, hyaluronic acid. , carrageenan, carboxymethylcellulose, alginates, sulfonated tetrafluoroethylene-based fluoropolymers such as Nafion®, poly(vinyl phosphate), poly(vinylphosphonic acid), and combinations thereof, including copolymers thereof. These include, but are not limited to:

The molecular weight of the polyelectrolyte polymer can vary from about 1,000 g/mole to about 1,000,000 g/mole. In some embodiments, the molecular weight (Mw) of the negatively charged anionic layer (eg, poly(acrylic acid)) ranges from 50,000 g/mole to 150,000 g/mole. In some embodiments, the molecular weight (Mw) of the positively charged cationic layer (eg, polydiallyldimethylammonium chloride) ranges from 50,000 g/mol to 300,000 g/mol. In some embodiments, the molecular weight (Mw) of the positively charged cationic layer (eg, poly(ethyleneimine)) ranges from 10,000 g/mole to 50,000 g/mole.

At least one of the polyions (eg, polyanion or polycation) includes a light absorbing material.

In order to be stable in water as a colloidal dispersion and to impart polyionic groups, the light-absorbing (eg pigment) particles typically further include an ionic surface treatment. In some embodiments, the surface treatment compound is anionic, such as a sulfonate or carboxylate. The light-absorbing (eg, pigment) particles also function as ionic binding groups for the alternating polyelectrolyte layers.

Suitable pigments are commercially available as colloidally stable aqueous dispersions from manufacturers such as Cabot, Clariant, DuPont, Dainippon and DeGussa. Particularly suitable pigments include the pigments available from Cabot Corporation under the name CAB-O-JET®, such as 250C (turquoise), 260M (magenta), 270Y (yellow) or 352K (black). It will be done. Light-absorbing (eg, pigment) particles are typically surface-treated to impart ionizable functional groups. Examples of suitable ionizable functional groups for light absorbing (eg, pigment) particles include sulfonate functional groups, carboxylate functional groups, and phosphoric acid or bisphosphonate functional groups. In some embodiments, surface-treated light-absorbing (eg, pigment) particles with ionizable functional groups are commercially available. For example, the CAB-O-JET® pigments sold under the trade names 250C (turquoise), 260M (magenta), 270Y (yellow) and 200 (black), commercially available from CABOT Corporation, are , containing a sulfonate functionality. As yet another example, CAB-O-JET® pigments, commercially available from CABOT Corporation under the trademarks 352K (black) and 300 (black), contain carboxylate functional groups.

If the light-absorbing (eg, pigment) particles are not pretreated, the light-absorbing (eg, pigment) particles may be surface-treated to impart ionizable functional groups, as is known in the art.

Multiple light absorbing materials (eg, pigments) can be utilized to achieve a particular hue or shade or color in the final product. When multiple light absorbing materials (eg pigments) are used, the materials are selected to ensure their compatibility and performance both with each other and with the optical product components.

In some embodiments, such as where the absorbing region includes carbon black, the light control film typically has a low transmittance (e.g., 10 %). When the absorbing regions are colored, the light control film can exhibit higher average transmittance. For example, the transmission may be 10-30% at a viewing angle of 30 degrees for wavelengths in the range 300 nm to 2400 nm. However, certain wavelength ranges may exhibit lower transmittance in the wavelength range of the color of the absorbing region. In some embodiments, the transmission is less than 15% at a viewing angle of 30 degrees for wavelengths in the range of 300 nm to 550 nm. In some embodiments, the transmission is less than 5, 4, 3, 2, or 1% at a viewing angle of 30 degrees for wavelengths in the range of 600 nm to 750 nm.

In a preferred embodiment, a polyelectrolyte is prepared and applied to the microstructured surface as an aqueous solution. The term "aqueous" means that the coating liquid contains at least 85 weight percent water. The coating liquid can contain higher amounts of water, such as at least 90, 95, or even at least 99 weight percent or more. The aqueous liquid medium can include a mixture of water and one or more water-soluble organic co-solvents in such amounts that the aqueous liquid medium forms a single phase. Examples of water-soluble organic cosolvents include methanol, ethanol, isopropanol, 2-methoxyethanol, 3-methoxypropanol, 1-methoxy-2-propanol, tetrahydrofuran, and ketone or ester solvents. The amount of organic co-solvent does not exceed 15% by weight of the total liquid of the coating composition. Aqueous polyelectrolyte compositions for use in layer-by-layer self-assembly typically include at least 0.01%, 0.05%, or 0.1% by weight polyelectrolyte; Specifically, it is 5% by weight, 4% by weight, 3% by weight, 2% by weight, or 1% by weight or less.

In some embodiments, the aqueous solution contains a "screening agent," an additive that promotes uniform and reproducible deposition by increasing ionic strength and decreasing interparticle electrostatic repulsion. Including further. Suitable screening agents include any low molecular weight salts such as halogen salts, sulfates, nitrates, phosphates, fluorophosphates, and the like. Examples of halogen salts include chloride salts such as LiCl, NaCl, KCl, _CaCl2 , _MgCl2 , _NH4Cl , etc., bromide salts such as LiBr, NaBr, KBr, _CaBr2 , _MgBr2 , etc., LiI, Examples include iodide salts such as NaI, KI, CaI ₂ , MgI ₂ , etc., fluoride salts such as NaF, KF, etc. Examples of sulfates include Li ₂ SO ₄ , Na ₂ SO ₄ , K ₂ SO ₄ , (NH ₄ ) ₂ SO ₄ , MgSO ₄ , CoSO ₄ , CuSO ₄ , ZnSO ₄ , SrSO ₄ , Al ₂ (SO ₄ ) ₃ and Fe ₂ (SO ₄ ) ₃ . Also, organic salts such as (CH ₃ ) ₃ CCl, (C ₂ H ₅ ) ₃ CCl, and the like are also suitable screening agents.

Appropriate screening agent concentrations may vary depending on the ionic strength of the salt. In some embodiments, the aqueous solution includes a screening agent (eg, NaCl) at a concentration ranging from 0.01M to 0.1M. The absorbent region can contain trace amounts of screening agents.

After applying the light-absorbing coating to the (e.g., entire) surface of the microstructured film and drying, the light-absorbing coating is removed from the top portions of the transparent (e.g., protrusions) areas and the transparent (e.g., protrusions) areas are The light absorbing coating is also removed from the land areas between them. It will be appreciated that the LCF can have improved on-axis transmission (eg, brightness) even if some of the light-absorbing coating is retained.

Any suitable method can be used to selectively remove light absorbing material from the top surfaces of the protrusions (eg, light absorbing regions) and the bottom surfaces of the channels.

In one embodiment, the light absorbing material is removed by reactive ion etching. Reactive ion etching (RIE) is a directional etching process that uses ion bombardment to remove material. Using a RIE system, organic or inorganic material is removed by etching the surface orthogonal to the direction of ion bombardment. The most notable difference between reactive ion etching and isotropic plasma etching is the etching direction. Reactive ion etching is characterized by a ratio of vertical to lateral etch rate greater than 1. The system for reactive ion etching is built around a durable vacuum chamber. Before starting the etch process, the chamber is evacuated to a base pressure of less than 1 Torr, less than 100 mTorr, less than 20 mTorr, less than 10 mTorr, or less than 1 mTorr. Electrodes hold the material to be processed and are electrically isolated from the vacuum chamber. The electrode may be a cylindrical rotatable electrode. A counter electrode is also provided within the chamber and may consist of the vacuum reactor wall. Gas containing etching reagents enters the chamber through a control valve. Process pressure is maintained by continuously evacuating chamber gases via a vacuum pump. The type of gas used will vary depending on the etching process. Etching typically involves carbon tetrafluoride ( _CF4 ), sulfur hexafluoride ( _SF6 ), octafluoropropane ( _C3F8 ), fluorofoam ( _{CHF3 )} , boron trichloride ( _BCl3 ), odor Hydrogen oxide (HBr), chlorine, argon and oxygen are used. RF power is applied to the electrodes and a plasma is generated. The sample can be transported through the plasma onto the electrode for a controlled period of time to achieve a specific etching depth. Reactive ion etching is known in the art and is further described in US Pat. No. 8,460,568, which is incorporated herein by reference.

In some embodiments, the reactive ion etching step causes the absorption region to be narrower (less than average width) near the bottom surface 311 of the channel. By removing the light-absorbing material, the depth of the channel can be increased (eg, slightly). After etching, a portion of the light absorbing material may remain.

After removing the light absorbing coating from the bottom of the channel, the channel can be filled with an organic polymeric material. In some embodiments, the organic polymeric material is a polymeric resin composition, and the method further includes curing (eg, radiation) the polymeric resin. Typically, the same polymeric resin used to make the microstructured film is utilized to fill the channels. Alternatively, different organic polymeric materials (eg, polymeric resin composites) are used. When different organic polymeric materials (eg, polymeric resin composites) are used, the composites are typically selected to match the refractive index for the light transmitting regions. "Refractive index matched" means that the difference in refractive index between the filler material and the transparent region is typically less than 0.1 or 0.005. Alternatively, it is possible to fill the channels with different organic polymeric materials (eg polymeric resin composites) whose refractive indices differ by more than 0.1. In yet another embodiment, the channels are not filled with organic polymeric material (eg, polymeric resin). In this embodiment, the channel typically contains air with a refractive index of 1.0.

If the channels are filled with a cured polymeric resin, the light control film can optionally include a cover film 470 bonded to the microstructured film using an adhesive 410. If the channel is filled with air, an adhesive film and a cover film are typically included.

In yet another embodiment, layer 410 may be a top coat rather than an adhesive. In this embodiment, cover film 470 may not be present.

FIG. 4 shows LCF 400 further including an optional cover film 470 that may be the same as base layer 260 or different. An optional cover film 470 can be bonded to the microstructured surface using adhesive 410. Adhesive 410 may be any optically clear adhesive, such as a UV curable acrylic adhesive, a transfer adhesive, etc.

Alternatively, the cover film can be contacted with a polymeric resin (eg, a backfill resin) that is utilized to fill the channels. The backfill resin is cured while in contact with the cover film, thereby bonding the cover film together.

One or more of the surfaces of the cover film may optionally be primed or otherwise treated to promote adhesion with an adhesive or backfill resin.

In typical embodiments, the thickness of the cover film can be at least about 0.025 millimeters (25 microns), and between about 0.05 mm (50 microns) and about 0.25 mm (250 microns). I can do it. In some embodiments, the cover film is a multilayer wavelength (eg, color) shifting film, as previously described.

The LCF can further include other coatings typically provided on exposed surfaces. A variety of hard coats, antireflective coatings, antireflective coatings, antistatic coatings, and antifouling coatings are known in the art. For example, U.S. Patent No. 7,267,850, U.S. Patent No. 7,173,778, PCT Publication No. WO2006/102383, PCT Publication No. WO2006/025992, No. 2006/025956, and U.S. Patent No. 7,575, See No. 847.

FIG. 5 shows a schematic perspective view of a backlit display 500 according to one embodiment. Backlit display 500 includes an LCF 530 with a transmissive region 540 and an absorbent region 550 as previously described. As described above, such an LCF has a polarity-blocking viewing angle θP of light exiting from the output surface 590 of the LCF 530. Backlit display 500 includes a light source 510 configured to transmit light through an image surface 520, such as an LCD panel, through LCF 530 and to a viewer 595. The viewing angle at which the brightness is maximum may depend on the polar cutoff viewing angle as already explained.

The backlit display 500 may also include an optional brightness enhancement film 560 and a reflective polarizer film 570 to further improve the brightness and uniformity of the display. The brightness enhancement film may be a prismatic film such as 3M™ Brightness Enhancement Film “BEF” or Thin Brightness Enhancement Film “TBEF” available from 3M Company. Reflective polarizer film 570 is manufactured by St. Louis, Minnesota. It may also be a multilayer optical film, such as 3M™ Dual Brightness Enhancement Film "DBEF" available from 3M Company, Paul. If included, brightness enhancement film 560 and reflective polarizer film 570 can be arranged as shown in FIG.

In other embodiments, a light control film with transmissive and absorbing regions as previously described can be coupled to an emissive (eg, organic light emitting diode or OLED) display.

In some embodiments, an LCF described herein (i.e., a first LCF) can be combined with a second LCF. In some embodiments, the second LCF is as described in U.S. Patent Nos. 6,398,370; 8,013,567; It may also be an LCF (e.g. a privacy film) as described. In other embodiments, the second LCF is an LCF as described herein (eg, the light absorbing region has an aspect ratio of at least 30). The first LCF and the second LCF can be stacked in various orientations.

In one embodiment, the first light control film and the second light control film are arranged such that the absorption area of the first LCF is parallel and typically coincident with the absorption area of the second LCF. Placed. In another embodiment, the first light control film and the second light control film are arranged such that the absorption region of the first LCF is orthogonal to the absorption region of the second LCF. Further, the first light control film and the second light control film can be arranged so that their absorption regions range from parallel to orthogonal to each other at a viewing angle of 0 degrees.

In some embodiments, the combination of the first LCF and the second LCF has a relative transmittance (e.g., luminance) of at least 60, 65, 70, 75, 80, 85, or 90% at a viewing angle of 0 degrees. have. In some embodiments, the relative transmittance (e.g., brightness) at a viewing angle of +30 degrees, -30 degrees, or an average of +30 degrees and -30 degrees is less than 25, 20, 15, 10, or 5%. . In some embodiments, the average relative transmittance (e.g., brightness) for viewing angles ranging from +35 to +80 degrees, -35 degrees to -85 degrees, or the average viewing angle of these ranges is 10, 9, 8, less than 7, 6, 5, 4, 3, 2, or 1%.

In some embodiments, the combination of LCFs has a relative transmittance (eg, brightness) of at least 60, 65, 70, 75, 80, 85, or 90% at a viewing angle of 0 degrees. In some embodiments, the relative transmittance (e.g., brightness) at a viewing angle of +30 degrees, -30 degrees, or an average of +30 degrees and -30 degrees is less than 25, 20, 15, 10, or 5%. .

When the channels are filled with air, the relative transmittance (eg, brightness) at larger viewing angles can be lower, and the film can therefore exhibit improved privacy.

The light control films described herein are particularly useful as components of display devices, as so-called hybrid privacy filters. A hybrid privacy filter can be used with a display surface, with light entering the hybrid privacy filter on the input side of the light control film and exiting the hybrid privacy filter or film stack in the color shifting film. The present invention is useful for laptop monitors, external computer monitors, mobile phone displays, televisions, smartphones, vehicle central information displays, vehicle driver information displays, vehicle side mirror displays (also referred to as electronic mirrors), consoles, or any other similar device. It can be used with a large number of electronic devices with displays including LCD, OLED, micro-LED or mini-LED based displays. A further advantage of applying a hybrid privacy filter to the display is improved contrast.

Other types of backlit display imaging, including non-electronic displays such as sunglasses, document cover sheets, console switches in automotive and aviation applications, airplane cockpit controls, helicopter cockpit controls, windows and any number of other objects Devices are also contemplated.

In yet other embodiments, the light control films described herein may be useful as canopies for glass and solar panels. For example, the light control film can be laminated onto or within the fenestration. Window partitions can be selected from glass panels, windows, doors, walls and skylight units. These glazings can be placed on the exterior or interior of the building. These may also be car windows, train windows, airplane passenger windows, ATMs, etc. Benefits of incorporating these film stacks into glazing include reduced IR transmission (which can lead to increased energy savings), ambient light blocking, privacy, and decorative effects.

In some examples, a light control film (LCF) disclosed herein may be part of an optical communication system. An "optical communication system" as referred to herein is a system for the communication of light over a distance from a light source through a disclosed LCF to a target, where the target is a detector or human eye. and the light source can include ambient light. Exemplary light sources include UV, visible or NIR emitting light emitting diodes (LEDs), laser sources including VCSELs (vertical cavity surface emitting lasers), halogen light sources, incandescent light sources, metal halide light sources, tungsten. Examples include light sources, mercury vapor light sources, short arc xenon light sources, or solar. In some cases, the LCFs disclosed herein can be part of an optical communication system with a detector system. In some cases, the detector system may provide various types of output, such as an electronic signal, upon receiving light passing through the LCF of the optical communication system. The detector system includes a detector sensitive to wavelengths within the detection wavelength range and an LCF disposed above the detector.

In some embodiments, the detector is or includes a photovoltaic device. The detector is configured to detect solar radiation, for example to charge a battery. In such cases, the detector may be or include a solar battery, solar cell, silicone photodiode or solar detector. In some cases, the detector may be a detector in a (eg, visible or near-infrared) camera for detecting and/or recording images. In some cases, the detector may reside within a camera or camera system. Other detectors include CMOS (complementary metal oxide semiconductor) and CCD (charge coupled device) detectors. Typical applications for photodetectors (also referred to herein as sensors) include gesture recognition, iris recognition, facial recognition, remote control and autonomous vehicles, ambient light sensors, proximity sensors, heart rate, blood oxygen, glucose. or other biological perception, 3D depth cameras with time-of-flight or structured light, security cameras.

In some cases, the light control film (LCF) disclosed herein may be part of an optical communication system that includes an optical structure in combination with the window shown in FIG. 7, for example. In this example, LCF 600 is part of an optical structure 601 that has a natural light source, such as sunlight 690. In particular, FIG. 7 shows an exemplary application of the disclosed LCF applied to a window to an enclosure such as a building, residence or vehicle. The LCF 600 can be placed on a window substrate 675 of a building, home, automobile, or any enclosure 670. The LCF 600 includes an optical film 650 that includes a plurality of spaced apart first absorbent regions 630 and an optional second (e.g., cover film) region 640 adjacent at least a portion of the at least one first region 630. including. The first region 630 can include a first absorbent material 632 and the second region 640 can include a second material 642.

In a preferred embodiment, the LCF window film exhibits high transmission of visible light in combination with low transmission of other UV and NIR light.

The transmittance of ultraviolet and infrared light by the first absorption region 630 varies as a function of the angle of incidence of the light. Specifically, when sunlight 690 enters the LCF 600 at a right angle, both infrared light and visible light can pass through the optical film 650. However, as the angle of incidence of light 690 from the sun increases, the amount of infrared light transmitted through the LCF 600 decreases until the angle of incidence reaches the viewing angle θP, from which point virtually all the infrared light is transmitted to the first material 632. That is, in the morning when the infrared portion of the sunlight 690 is relatively small and the sunlight 690 enters the window at a normal incidence angle, most of the infrared light can pass through the LCF 600. On the other hand, near noon, when the infrared part of the sunlight 690 is relatively large and the incident angle of the sunlight 690 becomes close to or larger than the viewing angle 2θv of the LCF 600, the incident infrared light The infrared rays of the infrared rays may be hardly transmitted and ultimately blocked, thus eliminating the possibility of exposing an observer or occupant 677 inside the building or residence 670 to hot infrared light. Therefore, the LCF 600 can reduce exposure to ultraviolet and infrared light.

FIG. 8 schematically depicts the relationship between detector sensitivity and wavelength, showing that the detector is sensitive to wavelengths within the detection wavelength range. As shown in FIG. 8, each first region of the disclosed LCF can have a substantially high transmittance in a predetermined first wavelength range "A" and a predetermined second wavelength range "A". a predetermined third wavelength range "C", wherein the second wavelength range B is They are respectively arranged between a first wavelength range A and a third wavelength range C. In some cases, the second wavelength range B is about 20 nm wide from the first wavelength 712 to the second wavelength 714 and is centered at the laser visible emission wavelength, and the first wavelength range A is about 20 nm wide from the first wavelength 712 to the second wavelength 714 400 nm to about the first wavelength 712, and the third wavelength range C is from about the second wavelength 714 to about 1400 nm. The laser visible emission wavelength may be at least one of 442nm, 458nm, 488nm, 514nm, 632.8nm, 980nm, 1047nm, 1064nm, and 1152nm. In other examples, the laser visible emission wavelength is within a range of about 416 nm to about 1360 nm. In other examples, the LCF can further include a plurality of spaced apart second regions alternating with the plurality of first regions, each second region having a predetermined first wavelength. range, the second wavelength range, and the third wavelength range. In other examples, the respective second regions can have a substantially low transmittance in either/and the predetermined first wavelength range and/or the third wavelength range. In some cases, the LCF has a viewing angle of less than about 60 degrees, or 50 degrees, or 40 degrees, or 30 degrees, or 20 degrees in the predetermined second wavelength range.

In another example application, the LCF disclosed herein may be part of an optical communication system having a separate light source, such as the laser light source shown in FIG.

In particular, FIG. 9 illustrates an exemplary application where the LCF is applied to an airplane or aircraft laser strike protection system to block incoming or incident light within a predetermined wavelength range. The LCF 800 can be attached to, for example, a plane, an airplane, or an aircraft 870, and preferably to a surface (such as a window) of the plane, airplane, or aircraft 870. The LCF 800 includes an optical fiber that includes a plurality of spaced apart first absorbing regions 830 and an optional second (e.g., cover film) region 840 adjacent at least a portion of at least one of the first regions 830. Includes film 850. First region 830 includes a first absorbent material 832 and second region 840 includes a second material 842.

When laser light 891 is incident on LCF 800, second (eg, cover film) material 842 absorbs and/or reflects at least a portion of the ultraviolet and infrared wavelength ranges, regardless of the angle of incidence of light 891. Furthermore, while the second (e.g., cover film) region 840 is transparent in a range of visible wavelengths, including the laser light 891 wavelength, the transmittance of visible light through the first region 830 is a function of the angle of incidence of the light. Change as. Visible light can be transmitted through optical film 850 when the light is incident at right angles to the surface of LCF 800. However, outside the viewing angle θP (see FIG. 1b), visible light is blocked by the first absorbing material 832 in the first region 830. Therefore, when using the LCF 800 on an airplane or aircraft 870, visible light from the laser beam 891 within the viewing angle θP can pass through the LCF 800, but ultraviolet and infrared light from the laser beam 891 can pass through the LCF 800. or only a limited amount of ultraviolet and infrared light, desirably less than about 10% of the ultraviolet and infrared light, respectively, can be transmitted through the LCF 800. Visible light can be transmitted through the LCF 800 as a function of the angle of incidence, including the wavelength of the light. Laser striker 878 may attack airplane or aircraft 870 using, for example, a green laser 890 to obstruct pilot 877's vision. Typically, the wavelength of green color is approximately 495 nm to 570 nm. Therefore, if the LCF 800 includes a first absorbing material 832 that blocks wavelengths of light in the range 495 nm to 570 nm, a pilot 877 on an airplane or aircraft 870 will be susceptible to a green laser strike by a ground-based laser striker 878. do not have.

In some cases, the disclosed light control films (LCFs) can be utilized in combination with retroreflectors. For example, FIG. 10 shows a retroreflective system 1101 that includes a retroreflective sheet 1190 for retroreflecting light and an LCF 1100 disposed on the retroreflective sheet 1190. Generally, retroreflector sheeting 1190 is configured to retroreflect light over a range of incident wavelengths and angles. For example, the retroreflector sheet 1190 can be configured to retroreflect light for different incident wavelengths λ ₁ and λ ₂ and different angles of incidence α and α′. By adding LCF 1100, system 1101 will have modified retroreflective properties. For example, for larger angles α and smaller angles α', the viewing angle θP of LCF 1100 is such that for smaller angles of incidence α', LCF 1100 is substantially transparent to light at both wavelengths λ ₁ and λ ₂ . and for larger angles of incidence α, the viewing angle may be such that the LCF substantially transmits light with wavelength λ ₁ and substantially absorbs light with wavelength λ ₂ . For example, in some cases, the viewing angle θP of LCF 1100 may be greater than α' and less than α. As another example, the retroreflective system 1101 is configured such that, for a first wavelength λ ₁ , light 810 and 810' incident on the LCF 1100 at corresponding first and second angles of incidence α' and α are both is configured to be retroreflected as retroreflected lights 812 and 812'. Furthermore, for a second wavelength λ ₂ , light 820 incident on the LCF at a first angle of incidence α' is retroreflected by retroreflected light 822, but is incident on the LCF at a second angle of incidence α. The light 820' that does is not retroreflected. In such cases, light 820' is absorbed by LCF 1100 when light 820' first enters the LCF, and in some cases light 820' is partially transmitted through the LCF and retroreflected. After being retroreflected by the sheet, it is absorbed by the LCF 1100. In some cases, LCF 1100 includes a larger first viewing angle for a first wavelength and a smaller viewing angle for a second wavelength. In some cases, the first angle of incidence α' is substantially equal to zero with respect to a line 801 perpendicular to the plane of LCF 1100. In some cases, retroreflective sheeting 1190 includes microsphere beads 610 to retroreflect light. In some cases, retroreflective sheeting 1190 includes corner cubes 620 to retroreflect light. In some cases, the LCF 1100 includes a plurality of spaced apart first regions 1130, each first region 1130 having a substantially low transmission at the second wavelength _λ2. However, it does not have a substantially low transmittance at the first wavelength λ ₁ .

In another case, the LCF can be used as part of an optical communication system with a sensor, more particularly a pulse sensor applied to a wrist watch as shown in FIG. In particular, FIG. 11 shows an exemplary application of an LCF applied to a wristwatch with a pulse sensor. LCF 1200 can be attached to wearable watch 1280 or any wearable device, and preferably to a surface of wearable watch 1280. LCF 1200 includes an optical film 1250 that includes a plurality of first absorbing regions 1230 and an optional second (eg, cover film) region 1240 adjacent at least a portion of at least one first region 1230. The first region 1230 can include a first absorbent material 1232 and the second region 1240 can include a second material 1242. The first material 1232 is spectrally selective in at least a portion of the visible light range from a light source, e.g. It may be any suitable material that is spectrally selective in at least a portion of at least one of the infrared light ranges. More desirably, the second material 1242 is spectrally selective in both the ultraviolet and infrared light ranges. When using the LCF 1200, from the perspective of the pulse sensor 1285, noise such as ultraviolet and infrared light is transmitted through the second material 1242 regardless of the angle of incidence of light from a light source such as sunlight 1295 or an LED 1290. is absorbed. Transmission of ultraviolet and infrared light from the light source through the second region 1240 is uniform regardless of the angle of incidence of the light, and is desirably less than about 10%. However, while the second region 1240 transmits a range of visible light from the LED 1290, the transmission of visible light through the first region 1230 varies as a function of the angle of incidence of the light. When the light from LED 1290 is incident at right angles to the surface of LCF 1200, visible light can be transmitted through optical film 1250. However, the first material 1232 blocks or reduces ambient visible light from sunlight 1295 or other light sources that is incident at a relatively large angle of incidence on the wrist 777 of the person wearing the device. Therefore, the LCF1200 has a signal (primarily visible light from LEDs incident within the viewing angle) versus noise (e.g. ultraviolet or infrared light, or e.g. sunlight incident outside the viewing angle, from other ambient light sources). (ambient visible light) ratio can be improved.

The above description should not be considered limited to the particular examples described herein, but rather encompasses all aspects of the description as expressly set forth in the appended claims. It should be understood that Upon reviewing this specification, various modifications, equivalent processes, and many structures will be readily apparent to those skilled in the art to which the above description is applicable. The above description can be better understood by considering the embodiments illustrated by the following test results and examples.

Embodiments of the invention Embodiment 1. A light control film comprising a light input surface, a light output surface opposite the light input surface, and alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, wherein the absorbing region is A light control film having an aspect ratio of at least 30, wherein the alternating transmitting and absorbing regions have a relative transmittance of at least 75% at a viewing angle of 0 degrees.

Embodiment 2. The light control film of embodiment 1, wherein the absorption region has a width parallel to the light input surface and a height perpendicular to the light input surface.

Embodiment 3. Embodiment 1, wherein the alternating transmitting and absorbing regions have a relative transmittance of less than 50, 45, 40, 35, 30, 25, 20, 10%, or 5% at a viewing angle of +30 degrees or -30 degrees. Or the light control film of 2.

Embodiment 4. Alternating transmission and absorption regions are 10, 9, 8, 7, 6, 5, for viewing angles in the range +35 to +80 degrees, or for viewing angles in the range -35 to -80 degrees. The light control film of embodiments 1-3 having an average relative transmittance of less than 4, 3, or 2%.

Embodiment 5. The light control film of embodiments 1-4, wherein the transparent region has a wall angle of less than 5, 4, 3, 2, 1, or 0.1 degrees.

Embodiment 6. The light control film of embodiments 1-5, wherein the transmitting and absorbing regions have heights in the range of 50-200 microns.

Embodiment 7. The light control film of embodiments 1-6, wherein the absorbing regions have an average width of less than or equal to 5, 4, 3, 2, 1, 0.5, 0.25, or 0.10 microns.

Embodiment 8. The light control film of embodiments 1-7, wherein the absorbing region has an aspect ratio of at least 50, 100, 200, 300, 400, 500, 600, 700, 800, or 1000.

Embodiment 9. The light control film of embodiments 1-8, wherein the absorbing regions have an average pitch of 10-200 microns.

Embodiment 10. The light control film of embodiments 1-9, wherein the transparent region has an aspect ratio of at least 2, 3, 4, 5, 6, 7, 8, 9, or 10.

Embodiment 11. The light control film of embodiments 1-10, wherein the absorbing region comprises an organic light absorbing material.

Embodiment 12. The light control film of embodiments 1-11, wherein the absorption region comprises light-absorbing particles having a median particle size of less than 500 nanometers.

Embodiment 13. The light control film of embodiments 1-12, wherein the absorption area comprises at least 25% by weight of light-absorbing particles.

Embodiment 14. The light control film of embodiments 1-13, wherein the absorption region comprises a polyelectrolyte.

Embodiment 15. The light control film of embodiments 1-14, wherein the transparent region comprises a radiation-cured (meth)acrylate polymer.

Embodiment 16. The light control film of embodiments 1-15, wherein alternating transmissive and absorbing regions are disposed on the base layer.

Embodiment 17. The light control film of embodiments 1 to 16, wherein the light control film further comprises a cover film.

Embodiment 18. The light control film of embodiments 1-16, wherein the light control film has a relative transmittance of at least 75% at a viewing angle of 0 degrees.

Embodiment 19. A light control film comprising the first light control film of claim 1 disposed on a second light control film.

Embodiment 20. The second light control film is according to claim 1, and the first light control film and the second light control film have absorption regions ranging from parallel to orthogonal to each other at a viewing angle of 0 degrees. 20. The light control film of claim 19, wherein the light control film is arranged in a range.

Embodiment 21. The second light control film is according to claim 1, and the first light control film and the second light control film are arranged such that their absorption areas coincide with each other at a viewing angle of 0 degrees. 20 light control films.

Embodiment 22. The light control film of embodiments 1 to 21, wherein the transmittance is for a wavelength range of 400 to 700 nm.

Embodiment 23. A microstructured film,
a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions having an aspect ratio of at least 30 and comprising an organic light absorbing material; area and
A microstructured film comprising:

Embodiment 24. 24. The microstructured film of claim 23, wherein the microstructured film is further characterized by any one of embodiments 2-22, or a combination thereof.

Embodiment 25. A microstructured film,
a light input surface and a light output surface opposite the light input surface;
Alternating transmissive and absorbing regions disposed between a light input surface and a light output surface, the absorbing regions comprising a plurality of particles having a median particle size of less than 100 nanometers. and an absorption region;
A microstructured film comprising:

Embodiment 26. A microstructured film,
a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions comprising a polyelectrolyte;
A microstructured film comprising:

Embodiment 27. 27. The microstructured film of embodiment 25 or 26, wherein the absorbing region has an aspect ratio of at least 30.

Embodiment 28. The microstructured film of embodiments 25-27, wherein the microstructured film is further characterized by any one of embodiments 2-22, or a combination thereof.

Embodiment 29. A method of manufacturing a light control film, the method comprising:
Provided is a microstructured film with a plurality of light transmissive regions interleaved with channels, the microstructured film having a surface defined by a top surface and sidewalls of the light transmissive regions and a bottom surface of the channel. , providing a microstructured film and applying an organic light absorbing material to the surface;
removing at least a portion of the light-absorbing coating from the top surface of the light-transmitting region and the bottom surface of the channel.

Embodiment 30. 30. The method of claim 29, wherein the organic light absorbing material comprises a polyelectrolyte.

Embodiment 31. 31. The method of embodiment 29 or 30, wherein the organic light-absorbing material comprises a plurality of light-absorbing particles.

Embodiment 32. The method of embodiments 29-31, wherein the light absorbing particles have an average particle size of less than 500 nm.

Embodiment 33. 33. The method of embodiments 29-32, wherein applying the light absorbing material comprises layer-by-layer self-assembly.

Embodiment 34. The method of embodiments 29-33, wherein the step of removing at least a portion of the light absorbing coating comprises reactive ion etching.

Embodiment 35. The method of embodiments 29-34, further comprising filling the channel with an organic polymeric material.

Embodiment 36. 36. The method of claim 35, wherein the organic polymeric material comprises a polymerizable resin, and the method further comprises curing the polymerizable resin.

Embodiment 37. A method of manufacturing a microstructured film, the method comprising:
Provided is a microstructured film with a plurality of light transmissive regions interleaved with channels, the microstructured film having a surface defined by a top surface and sidewalls of the light transmissive regions and a bottom surface of the channel. , providing a microstructured film, applying a light-absorbing material to the surface by layer-by-layer self-assembly, and removing at least a portion of the light-absorbing coating from the top surface of the light-transmitting region and the bottom surface of the channel. A method, including and .

Embodiment 38. 38. The method of claim 37, wherein the material is a light absorbing material.

Embodiment 39. 39. The method of embodiment 37 or 38, wherein the method further comprises removing at least a portion of the material from the top surface of the protrusion and the bottom surface of the channel.

Embodiment 40. The method of embodiments 37-39, wherein the method is further characterized by any one of embodiments 30-36, or a combination thereof.

Embodiment 41. A light detection system,
a light source configured to emit light having a first spectral profile along a first direction and a second spectral profile along a different second direction;
a detector sensitive to wavelengths within the detection wavelength range;
a light control film according to embodiments 1-28 disposed over the light source or detector for receiving and transmitting light emitted by the light source.

Embodiment 42. 42. The light detection system of embodiment 41, wherein the light source includes a light emitting diode (LED), a laser light source, a halogen light source, a metal halide light source, a tungsten light source, a mercury vapor light source, a short arc xenon light source, or the sun.

Embodiment 43. 43. The light detection system of embodiment 41 or 42, wherein the detector comprises a photovoltaic device, a solar battery, a solar cell, and a camera.

Embodiment 44. The light detection system of embodiments 41-43, wherein the light control film is disposed over the light source and the detector is remote.

Embodiment 45. The light detection system of embodiments 41-43, wherein the light control film is disposed over the detector and the light source is remote.

Embodiment 46. The light detection system of embodiments 41-45, wherein the light detection system is a vehicle sensor.

Embodiment 47. The light detection system of embodiments 41-46, wherein the light control film is disposed over the retroreflective sheeting.

Embodiment 48. 48. The optical detection system of embodiment 47, wherein the retroreflective sheet comprises at least one of microsphere beads and corner cubes.

Unless otherwise stated, all parts, percentages, ratios, etc. in the examples and the remainder of the specification are by weight. Unless otherwise noted, all chemical products are from St. Missouri, Missouri. Sigma-Aldrich Co., Louis. have been obtained or are available from chemical suppliers such as

Below is a list of materials used throughout the examples, as well as a brief description and origin thereof.

The components of Resin A used in the casting and curing microreplication process (Preparatory Example 1) and the index-matching backfill materials in Examples 2 and 4-8 are listed in Table 1 below. has been done. Raw materials for layer-by-layer coatings are listed in Table 2 below. Raw materials for reactive ion etching are listed in Table 3 below.

Preparatory Example 1 (PE1): Preparation of “square wave” microstructured film A tool with multiple parallel straight grooves was cut using a diamond (tip width 29.0 μm, included angle 3°, depth 87 μm). Ta. The grooves were spaced at a pitch of 62.6 microns.

Resin A was prepared by mixing the materials in Table 4 below.

A "cast and cure" high definition process was performed using Resin A and tools as described above. Line conditions were resin temperature 150°F, die temperature 150°F, coater IR edge 120°F/center 130°F, tool temperature 100°F and line speed 70 fpm using a Fusion D lamp (Maryland) with a peak wavelength of 385 nm. The resulting microstructured films were separated by channels as shown in Figure 2. The base layer 260 was a PET film (3M, St. Paul, Minn.) having a thickness of 2.93 mils (74.4 microns). The side of the PET film in contact with the resin was primed with a thermoset acrylic polymer (Rhoplex 3208 available from Dow Chemical, Midland, Michigan).The land layer (L) of cured resin was It had a thickness of 8 microns. The microstructured film is the topographical inverse of the tool such that the protrusions of the microstructured film are negative replicas of the tool grooves. The protrusions have 1.5 degree walls. angled and therefore the protrusion is slightly tapered (the light input surface is wider and the light output surface is narrower).The channels in the microstructured film are located in the non-cutting part of the tool between the grooves. It is a negative reproduction.

Method for producing layer-by-layer self-assembled coatings on microstructured films Layer-by-layer self-assembled coatings are manufactured by Svaya Nanotechnologies, Inc. (Sunnyvale, California) using equipment purchased from U.S. Pat. No. 8,234,998 (Krogman et al.), as well as Krogman et al. Modeled after the system described in Automated Process for Improved Uniformity and Versatility of Layer-by-Layer Deposition, Langmuir 2007, 23, 3137-3141 It was done.

The device includes a pressure vessel containing a coating solution. A spray nozzle (from Spraying Systems, Inc., Wheaton, Illinois) with a flat spray pattern was installed to spray the coating solution and rinse water at specific times controlled by solenoid valves. A pressure vessel (Alloy Products Corp., Waukesha, Wis.) containing the coating solution was pressurized to 30 psi with nitrogen, while a pressure vessel containing deionized (DI) water was pressurized to 30 psi with air. It was done. The flow rate from each coating solution nozzle was 10 gallons per hour, while the flow rate from the DI water rinse nozzle was 40 gallons per hour. The substrate to be coated was coated with a glass plate (12 in. x 12 in. /8 inch) (Brin Northwestern Glass Co., Minneapolis, Minn.), the glass plate was mounted on a vertical transition stage and held in place using a vacuum chuck. In a typical coating sequence, a polycation (eg, PDAC) solution was sprayed onto the substrate while the stage was moving vertically downward at 76 mm/s. Then, after a 12 second dwell time, DI water was sprayed onto the substrate while the stage was moving vertically upwards at 102 mm/sec. The substrate was then dried with an air knife at a speed of 3 mm/sec. A polyanion (eg, pigment nanoparticles) solution was then sprayed onto the substrate while the stage was moving vertically downward at 76 mm/sec. Another 12 second rest period was allowed to pass. DI water was sprayed onto the substrate while the stage was moving vertically upward at 102 mm/s. Finally, the substrate was dried with an air knife at a speed of 3 mm/sec. By repeating the above sequence, a number of "bilayers", denoted as (polycation/polyanion) _n , are deposited, where n is the number of bilayers. The coated substrate (eg, polymer film) was peeled from the glass substrate prior to subsequent processing.

Method for Reactive Ion Etching Microstructured Films Reactive ion etching (RIE) was performed in a parallel plate capacitively coupled plasma reactor. The chamber has a central cylindrical powered electrode with a surface area of 18.3 ft ² . After placing the microstructured film over the powered electrode, the reactor chamber was pumped down to a base pressure of less than 2 mTorr. A mixture of Ar (argon) and O ₂ (oxygen) gases were each flowed into the chamber at a rate of 100 SCCM. Processing was carried out using a plasma enhanced CVD method by coupling RF power into the reactor at a frequency of 13.56 MHz and an applied power of 6000 Watts. Processing time was controlled by moving the microstructured film through the reaction zone. Following this treatment, the RF power and gas supplies were stopped and the chamber was returned to atmospheric pressure. Additional information regarding the materials, the process for applying cylindrical RIE, and further details about the reactor surroundings used can be found in US Pat. No. 8,460,568 (B2).

Method for Backfilling Channels in Microstructured Film Pipette the resin between the microstructured film surface and a 3 mil thick piece of unprimed PET film placed on top, using a hand roller. The top PET film is then UV cured using a HERAEUS (Hanau, Germany) belt conveyor UV processor (model number DRS(6)) with a 500 watt power "H" bulb. As a result, the resin A used in PE1 was backfilled into the channel. Specifically, the sample was sent through the UV curing station three times at a transport speed of 50 ft/min. The top PET film was then manually peeled off from the microstructured film.

Method for Measuring Luminance Profiles from Diffuse Light Sources A sample of film was placed above a Lambertian light source. If the light transmissive area is tapered, the film is positioned such that the widest part of the tapered area is closer to the light source. Light output was detected simultaneously in a hemispherical manner at all polarities and azimuths using an Eldim L80 conoscope (Eldim S.A., HEROUVILLE SAINT CLAIR, France). After detection, cross-sections of transmittance (e.g., brightness) readings were taken in a direction perpendicular to the direction of the louvers (denoted as a 0° orientation angle), unless otherwise indicated. Relative transmission (ie, visible light brightness) is expressed as the percentage of on-axis brightness at a particular viewing angle between the readings with and without the film.

The Lambertian light source consisted of diffuse transmission from a light box with the baseline brightness profile shown in FIG. The light box was a six-sided hollow cube approximately 12.5 cm x 12.5 cm x 11.5 cm (L x W x H) fabricated from diffused polytetrafluoroethylene (PTFE) plates ˜6 mm thick. One side of this box was selected as the sample surface. The hollow light box had a refractive index of ~0.83 (eg, ~83% averaged over the wavelength range of 400-700 nm) measured at its sample surface. During testing, the box was illuminated from the inside through a ˜1 cm circular hole in the bottom of the box (opposite the sample surface; light was directed from the inside towards the sample surface). Illumination was provided using a stabilized broadband incandescent light source attached to a fiber optic bundle used to direct the light (1 cm diameter from Schott-Fostec LLC, Marlborough, Massachusetts, and Auburn, New York). Fostec DCR-II with fiber bundle extensions).

Method for measuring the transmittance of ultraviolet light and near-infrared light The transmittance of ultraviolet light (320-400 nm) and near-infrared light (700-1400 nm) is measured using a variable angle transmittance sample holder (catalog number PELA9042). (Perkin Elmer, Waltham, Massachusetts) with a Lambda 1050 spectrophotometer (Perkin Elmer, Waltham, Massachusetts). Values reported in the examples are from the specified 320-400 nm (ultraviolet) or 700-1400 nm (near infrared) measured at a single location on an individual sample, and also from the specified is the arithmetic mean of the transmittance at either +30° or +60° angle of incidence.

Methods for Cross-Sectional Scanning Electron Microscopy (SEM) Cross-sections were prepared via freeze-fracture using liquid nitrogen. SEM images were acquired using a Hitachi SU-8230 (Hitachi, Ltd., Tokyo, Japan) instrument.

Comparative Examples 1-2 (CE1-CE-2) are commercially available light control films.
Comparative example 3 (CE3)
Two sections (3 inches by 3 inches each) of film from CE1 were overlapped and laminated with an optically clear adhesive (8171, 3M Company, St. Paul, Minnesota). One sheet was oriented at right angles to the other. That is, the original direction of the channels was offset by 90° between the top and bottom sheets.

Preparation Example 2 (PE2): Preparation of Coating Solution PDAC was diluted with deionized (DI) water to a concentration of 20% to 0.32% by weight. PAA was diluted from 25% to a concentration of 0.1% by weight and the pH was adjusted to 4.0 with 1M NaOH. CAB-O-JET (registered trademark) 200 (COJ200), CAB-O-JET (registered trademark) 250C (COJ250C), CAB-O-JET (registered trademark) 260M (COJ260M) and CAB-O-JET (registered trademark) ) 352K (COJ352K) were each diluted with DI water to a concentration of 0.10% by weight. NaCl was added to both the PDAC solution and the pigment suspension to a concentration of 0.05 M. 1M NaOH was added to the COJ352K suspension until pH 9. pH values were measured using a VWR (West Chester, Pennsylvania) pH electrode (catalog number 89231-582) calibrated with standard buffer solutions.

Preparation Example 3 (PE3): Preparation of Cationic Pigment A polyethyleneimine (PEI) modified CAB-O-JET® 352K (COJ352K) carbon black nanopigment, abbreviated as PEI-COJ352K, was prepared as follows. Ta. PEI (MW 25K) was diluted to make a 10% by weight solution. A 10 wt% PEI solution weighing 3.2 grams was diluted with DI water to a mass of 794.7 grams. Next, 5.3 grams of as-received COJ352K at 15.03% solids was added dropwise to the 794.7 grams PEI solution with vigorous magnetic stirring, thereby adding 0.1% by weight COJ352K and 0.1% by weight COJ352K. A final concentration of 0.04% PEI by weight was obtained. The size and zeta potential of polyethyleneimine (PEI) modified CAB-O-JET® 352K (COJ352K) were determined using an aliquot of the above PEI-COJ352K sample diluted 100 times with 1 mM KCl from Brookhaven Instruments. Corp. (Holtsville, New York) using a ZetaPALS instrument. The particle sizes were described as d ₁₀ =77.5 nm, d ₅₀ =148.4 nm, and d ₉₀ =284.0 nm. The measured zeta potential was +37.9±0.9 mV.

Example 1 (EX1): Carbon black nanopigment, 130 nm diameter, no backfill A sheet of microstructured film made with PE1 was cut to a size of 9 inches by 10 inches and subjected to beading up and dewetting of an aqueous coating solution. The samples were corona treated by hand using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Ill.) to prevent staining. PDAC and CAB-O-JET® 200 coating solutions were made as described for PE2. Corona-treated films were coated with (PDAC/COJ200) ₁₀ using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films". The coated film was subjected to reactive ion etching (RIE) with a power of 6000 W for a duration of 210 seconds. The equivalent coating thickness deposited on the glass plate was 166 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. . Based on the equivalent coating thickness deposited on the glass, the aspect ratio of the absorbing regions (eg, louvers) was approximately 525:1.

Example 2 (EX2): Carbon black nanopigment, 130 nm diameter, with backfill A sheet of microstructured film made of PE1 was cut to a size of 9 inches x 10 inches and subjected to beading up and dewetting of an aqueous coating solution. The samples were corona treated by hand using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Ill.) to prevent staining. PDAC and CAB-O-JET® 200 coating solutions were made as described for PE2. Corona-treated films were coated with (PDAC/COJ200) ₂₀ using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films". The coated film was subjected to reactive ion etching (RIE) with a power of 6000 W for a duration of 210 seconds. The channels were then backfilled using the "Method for Backfilling Channels in Microstructured Films" described above. The equivalent coating thickness deposited on the glass plate was 326 nm as measured with a Dektak XT stylus profilometer after scoring the coating with a razor blade.

Example 3 (EX3): Carbon black nanopigment, 70-80 nm diameter, no backfill A sheet of microstructured film made of PE1 was cut to a size of 9 inches x 10 inches and treated with beading-up and aqueous coating solution. Corona treatment was performed by hand using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Ill.) to prevent dewetting. PDAC and CAB-O-JET® 352K coating solutions were made as described for PE2. Corona-treated films were coated with (PDAC/COJ352K) ₂₀ using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films". The coated film was then subjected to reactive ion etching (RIE) with a power of 6000 W for a duration of 200 seconds. The equivalent coating thickness deposited on the glass plate was 273 nm as measured with a Dektak XT stylus profilometer after scoring the coating with a razor blade.

Examples 4-6 (EX4-6): Carbon black nanopigment, diameter 70-80 nm, with backfill Three sheets of microstructured film made of PE1 were each cut to a size of 9 inches by 10 inches; The aqueous coating solution was manually corona treated using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Ill.) to prevent beading up and dewetting of the aqueous coating solution. PDAC and CAB-O-JET® 352K coating solutions were made as described for PE2. Individual 9" x 10" pieces of corona-treated film were prepared using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films" (PDAC/COJ352K) ₂₀ (EX4), (PDAC/COJ352K) ₄₀ (EX5) and (PDAC/COJ352K) ₆₀ (EX6). The coated films were subjected to reactive ion etching (RIE) with a power of 6000 W for durations of 200 seconds (EX4) and 500 seconds (EX5 and EX6). Cross-sectional SEM images of EX4 were taken before and after RIE and before backfilling. From the SEM images, the coating deposited on top of the film is a coating of uniform thickness, and its thickness corresponds to the equivalent coating deposited on glass, as explained below. was obvious. The channels were then backfilled using the "Method for Backfilling Channels in Microstructured Films" described above. The brightness profile from the diffuse light source was measured using the "Method for Measuring the Brightness Profile from the Diffuse Light Source" described above (data is shown in FIG. 6 and Tables 5A and 5B). The equivalent coating thickness deposited on the glass plate was 273 nm (EX4), 536 nm (EX5) and 796 nm (EX6) as measured with a Dektak XT stylus profilometer after scoring the coating with a razor blade. . Based on the thickness of the equivalent coating deposited on the glass, the aspect ratio of the absorbing regions (eg, louvers) ranged from approximately 109:1 (for EX6) to 319:1 (for EX4).

Example 7 (EX7): Superimposed Cross Film Two sections (3 inches by 3 inches each) of light control film prepared according to EX4 were prepared with structured sides facing each other and one sheet facing the other. They were stacked so that they were oriented at right angles to. That is, the original direction of the channels was offset by 90° between the top and bottom sheets. Resin A was distributed between the two sheets, and the two sheets were laminated together with a hand roller. The samples were cured as described in "Method for Backfilling Channels in Microstructured Films" and measured using "Method for Measuring Brightness Profiles from Diffuse Light Sources." The data are shown in Tables 6A and 6D.

Example 8 (EX8): Superimposed Alignment Film Two sections (3 inches by 3 inches each) of light control film prepared according to EX4 were prepared with structured sides facing each other and one sheet facing the other. They were stacked so that they were oriented parallel to each other. That is, the original direction of the channels was aligned between the top and bottom sheets. Resin A was distributed between the two sheets, and the two sheets were laminated together with a hand roller. The samples were cured as described in "Method for Backfilling Channels in Microstructured Films" and measured using "Method for Measuring Brightness Profiles from Diffuse Light Sources." The data are shown in Tables 6A-6D.

Example 9A (EX9A): Cyan nanopigment coating, no backfill Microstructured sheets of film made with PE1 are cut to size 9 inches x 10 inches to prevent beading up and dewetting of aqueous coating solutions. The specimens were corona treated by hand using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Illinois). PDAC and CAB-O-JET® 250C coating solutions were made as described for PE2. Corona-treated films were coated with (PDAC/COJ250C) ₂₀ using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films." The coated film was subjected to reactive ion etching (RIE) with a power of 6000 W for a duration of 150 seconds. Relative brightness was measured using the "Method for Measuring Brightness Profiles from Diffuse Light Sources" (data shown in Table 7). The equivalent coating thickness deposited on the glass plate was 340 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. .

Example 9B (EX9B): Cyan nanopigment coating with backfilling Same as described in 9A except that the channels were backfilled using the "Method for Backfilling Channels in Microstructured Films" described above. The above sheet of film was prepared as follows. Relative brightness was measured using the "Method for Measuring Brightness Profiles from Diffuse Light Sources" (data shown in Table 7). The equivalent coating thickness deposited on the glass plate was 340 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. .

Example 10A (EX10A): Magenta Nanopigment Coating, No Backfill Microstructured sheets of film made with PE1 were cut to size 9 inches x 10 inches to prevent beading up and dewetting of the aqueous coating solution. The specimens were corona treated by hand using a BD-20AC Laboratory Corona Treater (Electro-Technic Products, Chicago, Ill.). PDAC and CAB-O-JET® 260M coating solutions were made as described for PE2. Corona-treated films were coated with (PDAC/COJ260M) ₂₀ using the "Method for Building Sprayed Layer-by-Layer Self-Assembled Coatings on Microstructured Films". The coated film was subjected to reactive ion etching (RIE) with a power of 6000 W for a duration of 150 seconds. Relative brightness was measured using the "Method for Measuring Brightness Profiles from Diffuse Light Sources" (data shown in Table 7). The equivalent coating thickness deposited on the glass plate was 313 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. .

Example 10B (EX10B): Magenta Nanopigment Coating, Backfilled As described in 10A except that the channels were backfilled using the "Method for Backfilling Channels in Microstructured Films" described above. A microstructured sheet of film was prepared as described. Relative brightness was measured using the "Method for Measuring Brightness Profiles from Diffuse Light Sources" (data shown in Table 7). The equivalent coating thickness deposited on the glass plate was 313 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. .

Example 11 (EX11): Cationic Pigment, Anionic Polyelectrolyte Glass microscope slides 1 inch by 3 inches in size (Fisher Scientific, Waltham, Mass.) were rinsed with DI water and isopropanol. Slides were mounted on a StratoSequence VI (nanoStrata, Inc., Tallahassee, Fla.) automatic layer-by-layer dip coater. The slides were immersed in the PEI-COJ352K solution described in PE3 for 1 minute. The slides were then immersed in three successive DI water rinse baths for 30 seconds each. The slides were then immersed in PAA solution (0.1% by weight, adjusted to pH 4 with HCl) for 1 minute. The slides were then immersed in three successive DI water rinse baths for 30 seconds each. Slides were rotated at 150 rpm in individual baths. This cycle was repeated for a total of 10 times to deposit (PEI-COJ352K/PAA) ₁₀ . The thickness of the coating was 4 μm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. Microstructured films of PE1 can be coated layer by layer with this composite and subjected to RIE as previously described.

Example 12 (EX12): Cationic Pigment, Anionic Pigment Glass microscope slides (Fisher Scientific, Waltham, Mass.), 1 inch by 3 inches in size, were rinsed with DI water and isopropanol. Slides were mounted on a StratoSequence VI (nanoStrata, Inc., Tallahassee, Fla.) automated layer-by-layer dip coater. Slides were immersed in PEI-COJ352K solution (as described in PE3) for 1 minute. The slides were then immersed in three successive DI water rinse baths for 30 seconds each. The slides were then immersed in COJ352K solution (as described for PE2) for 1 minute. The slides were then immersed in three successive DI water rinse baths for 30 seconds each. Slides were rotated at 150 rpm in individual baths. This cycle was repeated for a total of 10 times to deposit (PEI-COJ352K/COJ352K) ₁₀ . The coating thickness was 240 nm as measured with a Dektak XT stylus profilometer (Bruker Nano, Inc., Tucson, Arizona) after scoring the coating with a razor blade. Microstructured films of PE1 can be coated layer by layer with this composite and subjected to RIE as previously described.

Example 13 (EX13)
A light control film was prepared as described in EX1. During the method of backfilling the channels of the microstructured film, the top PET film was replaced with a color shift film as described in Example 1 of WO 2010/1090924. After UV curing the backfilled channels, the color shift film was not peeled off, but instead was retained as a cover film.

A highly reflective color shifting film will cause light recirculation within the gain cube resulting in on-axis relative brightness greater than 100%.

Surface Area of Absorption Region The light input surface of CE2 was observed under an optical microscope at 200x magnification. The maximum width (i.e., W _A in Fig. 1a) and pitch (i.e., P _A in Fig. 1a) of the multiple absorbing regions were obtained from the National Institute of Health at ImageJ software (website http://imagej.nih.gov/ij). was measured by analyzing light microscopy images using a The average width of the five absorption regions was determined to be 14.7 microns. The average pitch was determined to be 64.9 microns. The ratio W _A /P _A is therefore equal to 0.227, or 22.7% of the surface area.

The light input surface of EX6 was observed under an optical microscope at 200x magnification. The maximum width (i.e., W _A in Fig. 1a) and pitch (i.e., P _A in Fig. 1a) of the multiple absorbing regions were obtained from the National Institute of Health at ImageJ software (website http://imagej.nih.gov/ij). was measured by analyzing light microscopy images using a The average width of the five absorption regions was determined to be 1.0 micron. The average pitch was determined to be 31.2 microns. If the wall angle is zero, the ratio W _A /P _A is equal to 0.032, or 3.2% of the surface area. If the wall angle is 1.5 degrees, the surface area is 10.8%. Exemplary embodiments are shown below.
[1]
a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions having an aspect ratio of at least 30; measured at a viewing angle of 0 degrees using a spectrophotometer,
i) at least 35, 40, 45, or 50% for wavelengths in the range 320-400 nm (UV), or
ii) at least 65, 70, 75, or 80% for wavelengths in the range 700-1400 nm (NIR);
or a combination thereof,
alternating transmitting and absorbing regions having a transmittance of
A light control film comprising:
[2]
The light control according to [1], wherein the absorption region has a width parallel to the light input surface and a height perpendicular to the light input surface, and the height is larger than the width. film.
[3]
the alternating transmitting and absorbing regions have a visible light relative transmittance of less than 50, 45, 40, 35, 30, 25, 20, 10% or 5% at a viewing angle of +30 degrees or -30 degrees; The light control film according to [1] or [2].
[4]
10, 9, 8, 7, 6, 5, 4, for viewing angles in the range of +35 to +80 degrees, or viewing angles in the range of -35 to -80 degrees, the alternating transmitting and absorbing regions The light control film according to [1] to [3], which has a visible light average relative transmittance of 3% or less than 2%.
[5]
The light control film according to [1] to [4], wherein the transparent region has a wall angle of less than 5, 4, 3, 2, 1, or 0.1 degrees.
[6]
The light control film according to [1] to [5], wherein the transmission region and the absorption region have a height in the range of 50 to 200 microns.
[7]
The light control film according to [1] to [6], wherein the absorption region has an average width of 5, 4, 3, 2, 1, 0.5, 0.25, or 0.10 microns or less.
[8]
The light control film according to [1] to [7], wherein the absorption region has an aspect ratio of at least 50, 100, 200, 300, 400, 500, 600, 700, 800, or 1000.
[9]
The light control film according to [1] to [8], wherein the absorption region has an average pitch of 10 to 200 microns.
[10]
The light control film according to [1] to [9], wherein the transmission region has an aspect ratio of at least 2, 3, 4, 5, 6, 7, 8, 9, or 10.
[11]
The light control film according to [1] to [10], wherein the absorption region contains an organic light absorption material.
[12]
The light control film according to [1] to [11], wherein the absorption region includes light absorption particles having a median particle size of less than 500 nanometers.
[13]
The light control film according to [1] to [12], wherein the absorption region contains at least 25% by weight of light-absorbing particles.
[14]
The light control film according to [1] to [13], wherein the absorption region contains a polymer electrolyte.
[15]
The light control film according to [1] to [14], wherein the transmission region includes a radiation-cured (meth)acrylate polymer.
[16]
The light control film according to [1] to [15], wherein the alternating transmission regions and the absorption regions are arranged on a base layer.
[17]
The light control film according to [1] to [16], wherein the light control film further includes a cover film.
[18]
The light control film according to [1] to [17], wherein the base layer or cover film is a multilayer film.
[19]
The light control film according to [18], wherein the multilayer film is a color shift film, a UV reflective film, a UV blue reflective film, or a near-infrared reflective film.
[20]
[1] to [19] wherein said alternating transmitting and absorbing regions have a relative transmittance of at least 75% measured with a conoscope for a wavelength range in the range of 400 to 700 nm at a viewing angle of 0 degrees. The light control film described in ].
[21]
[1] to [20], wherein the light control film has a relative transmittance measured with a conoscope of at least 75% for a wavelength range ranging from 400 to 700 nm at a viewing angle of 0 degrees. light control film.
[22]
The light control film has a transmittance of at least 60, 65, 70, 75, or 80% for wavelengths in the range of 700 to 1400 nm (NIR) and in the range of 320 to 400 nm (UV) at a viewing angle of 0 degrees. The light control film according to [1] to [21], which has a transmittance of less than 50, 45, 40, 35, 30, 25, 20, or 15% for wavelengths of.
[23]
The light control film has an average transmittance of at least 10, 15, 20, 25, 30, 35, 40, 45, or 50% for a wavelength range ranging from 700 to 1400 nm (NIR) at a viewing angle of 30 degrees. The light control film according to [1] to [22], which has the following.
[24]
The light control film has an average transmittance of at least 10, 15, 20, 25, 30, 35, 40, 45, or 50% for a wavelength range ranging from 700 to 1400 nm (NIR) at a viewing angle of 60 degrees. The light control film according to [1] to [23], which has the following.
[25]
A light control film comprising the first light control film according to [1] to [24], which is disposed on a second light control film.
[26]
The second light control film is the light control film according to [1] to [24], and the first light control film and the second light control film are arranged in the absorption area at a viewing angle of 0 degrees. The light control film according to [25], wherein the light control film is arranged in a range from parallel to orthogonal to each other.
[27]
The second light control film is the light control film according to [1] to [24], and the first light control film and the second light control film are arranged in the absorption area at a viewing angle of 0 degrees. The light control film according to [26], wherein the light control film is arranged so that they coincide with each other.
[28]
a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions having an aspect ratio of at least 30; alternating transmissive and absorbing regions that block light by surface area, the maximum surface area being less than 20% of the total of the alternating transmissive regions and the absorbing regions;
A light control film comprising:
[29]
The light control film according to [28], wherein the absorption region has an aspect ratio of at least 30.
[30]
The alternating transmitting and absorbing regions or the light control film has a relative transmittance of at least 75% measured conoscopically for a wavelength range of 400 to 700 nm at a viewing angle of 0 degrees [28 ] or the light control film according to [29].
[31]
The alternating transmitting and absorbing regions, or the light control film, has a wavelength of at least 35,40 nm for wavelengths in the range of 320-400 nm (UV), measured at a viewing angle of 0 degrees using a spectrophotometer. , 45, or 50%, the light control film according to [28] to [30].
[32]
The alternating transmitting and absorbing regions, or the light control film, has at least a , 75, or 80%, or a combination thereof, the light control film according to [28] to [31].
[33]
The light control film according to [1] to [32], wherein the light control film is characterized by [2] to [27].
[34]
a light source configured to emit light having a first spectral profile along a first direction and a second spectral profile along a different second direction;
a detector sensitive to wavelengths within the detection wavelength range;
The light control film according to [1] to [33], which is disposed on the light source or the detector and is configured to receive and transmit light emitted by the light source;
including a light detection system.
[35]
The light detection system according to [34], wherein the light source includes a light emitting diode (LED), a laser light source, a halogen light source, a metal halide light source, a tungsten light source, a mercury vapor light source, a short arc xenon light source, or the sun.
[36]
The photodetection system according to [34] or [35], wherein the detector comprises a photovoltaic device, a solar battery, a solar cell, and a camera.
[37]
A light detection system according to [34] to [36], wherein the light control film is placed above the light source and the detector is remote.
[38]
The light detection system according to [34] to [36], wherein the light control film is placed on the detector and the light source is remote.
[39]
The light detection system according to [34] to [38], wherein the light detection system is a vehicle sensor.
[40]
The light detection system according to [34] to [39], wherein the light control film is placed on a retroreflective sheet.
[41]
The photodetection system according to [40], wherein the retroreflective sheet includes at least one of microsphere beads and corner cubes.

Claims (19)

a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions having an aspect ratio of at least 30; measured at a viewing angle of 0 degrees using a spectrophotometer,
i) at least 35% for wavelengths in the range 320-400 nm (UV), or ii) at least 65% for wavelengths in the range 700-1400 nm (NIR),
or a combination thereof,
alternating transmitting and absorbing regions having a transmittance of
Equipped with
The absorption region is
i) an average width of 5 microns or less, and
ii) an aspect ratio of at least 50;
A light control film with . The light control according to claim 1, wherein the absorption region has a width parallel to the light input surface and a height perpendicular to the light input surface, and the height is larger than the width. film. 3. The light control film of claim 1 or 2, wherein the alternating transmitting and absorbing regions have a visible light relative transmittance of less than 50% at a viewing angle of +30 degrees or -30 degrees. 4. The alternating transmitting and absorbing regions have an average relative transmittance of visible light of less than 10% for viewing angles in the range of +35 to +80 degrees, or viewing angles in the range of -35 to -80 degrees. The light control film according to items 1 to 3. The transparent region is
i) wall angle less than 5 degrees ;
ii) height in the range of 50-200 microns;
iii) an aspect ratio of at least 2 ;
iv) or a combination thereof;
The light control film according to any one of claims 1 to 4, comprising: The absorption region is
i ii) average pitch between 10 and 200 microns ;
The light control film according to any one of claims 1 to 5, comprising : The absorption region is i) an organic light absorption material ;
The light control film according to any one of claims 1 to 6, comprising : The absorption area is
ii) light absorbing particles having a median particle size of less than 500 nanometers;
The light control film according to any one of claims 1 to 7, comprising: The absorption area is
iii) at least 25% by weight of light absorbing particles;
The light control film according to any one of claims 1 to 8, comprising: The absorption area is
iv) polyelectrolyte,
The light control film according to any one of claims 1 to 9, comprising: The absorption area is
v) radiation-cured (meth)acrylate polymer;
The light control film according to any one of claims 1 to 10, comprising: the alternating transmissive regions and the absorbent regions are disposed on a base layer, or the light control film further comprises a cover film;
the base layer or cover film is a multilayer film selected from a color shift film, a UV reflective film, a UV blue reflective film or a near-infrared reflective film;
The light control film according to claims 1 to 11 . The first light control film according to any one of claims 1 to 12 is disposed on a second light control film, wherein the first light control film and the second light control film are arranged at 0 degrees. a light control in which the absorption regions are arranged to range from parallel to orthogonal to each other at a viewing angle, or arranged such that at a viewing angle of 0 degrees the absorption regions are coincident with each other; film. a light input surface and a light output surface opposite the light input surface;
alternating transmissive and absorbing regions disposed between the light input surface and the light output surface, the absorbing regions having an aspect ratio of at least 30; alternating transmissive and absorbing regions that block light by surface area, the maximum surface area being less than 20% of the total of the alternating transmissive regions and the absorbing regions;
Equipped with
The absorption region is
i) an average width of 5 microns or less, and
ii) an aspect ratio of at least 50;
A light control film with . a light source configured to emit light having a first spectral profile along a first direction and a second spectral profile along a different second direction;
a detector sensitive to wavelengths within the detection wavelength range;
The light control film according to any one of claims 1 to 14 , which is disposed on the light source or the detector and is configured to receive and transmit light emitted by the light source.
including a light detection system. 16. The light detection system of claim 15 , wherein the light source comprises a light emitting diode (LED), a laser light source, a halogen light source, a metal halide light source, a tungsten light source, a mercury vapor light source, a short arc xenon light source, or the sun. 17. A light detection system according to claim 15 or 16 , wherein the detector comprises a photovoltaic device, a solar battery, a solar cell, or a camera. 18. According to claims 15-17 , the light control film is arranged above the light source and the detector is remote; or the light control film is arranged above the detector and the light source is remote. The optical detection system described. A light detection system according to claims 15 to 18 , wherein the light detection system is a vehicle sensor.

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